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QUALITATIVE  CHEMICAL  ANALYSIS.  A  Guide 
in  Qualitative  Work,  with  data  for  Analytical 
Operations  and  Laboratory  Methods  in  Inorganic 
Chemistry,  by  ALBERT  B.  PRESCOTT  and  OTIS  C. 
JOHNSON,  Professors  in  the  University  of  Michigan. 
Fifth  revised  and  enlarged  edition,  entirely 
rewritten.  8vo,  cloth $3. SO  Net. 


OUTLINES  OF  PROXIMATE  ORGANIC  ANALY- 
SIS :  For  the  Identification,  Separation,  and 
Quantitative  Determination  of  the  more  Com- 
monly Occurring  Organic  Compounds.  Fourth 
edition.  12mo,  cloth $1.75 


FIRST  BOOK  IN  QUALITATIVE   CHEMISTRY. 
Tenth  edition,  revised.    12mo,  cloth $1.5O 


ORGANIC  ANALYSIS: 


A  MANUAL 


OF    THE    DESCRIPTIVE    AND    ANALYTICAL    CHEMISTRY    OF 
CERTAIN  CARBON  COMPOUNDS  IN  COMMON  USE. 


QUALITATIVE     AND     QUANTITATIVE     ANALYSIS    OF    ORGANIC     MATERIALS: 

COMMERCIAL    AND    PHARMACEUTICAL   ASSAYS;     THE   ESTIMATION 

OF  IMPURITIES  UNDER  AUTHORIZED  STANDARDS  ;  FORENSIC 

EXAMINATIONS  FOR  POISONS ;  AND  ELEMENTARY 

ORGANIC  ANALYSIS. 


BY 


ALBERT  B.  PRESCOTT,  PH.D.,  M.D., 

Director  of  the  Chemical  Laboratory  in  the  University  of  Michigan,  Author  of 

"  Outlines  of  Proximate  Organic  Analysis,"  "  Qualitative  Chemical 

Analysis"  etc. 


FIFTH  EDITION. 
NEW  YORK: 

D.  VAN  NOSTRAND  COMPANY, 

23  MURRAY  A1TD  27  WARREN  STREET. 
1901. 


COPTBIGHT,  1887, 

BY  W.  H.  FAKRINGTON. 


GENERAL 


PREFACE. 


THE  operator  in  chemical  analysis  requires  for  his  direction 
a  system  of  descriptive  chemistry,  to  be  as  nearly  complete  as 
possible.  In  resorting  to  the  hand-books  of  general  chemistry 
for  the  record  of  physical  and  chemical  constants  the  analyst  is 
often  disappointed.  It  belongs,  therefore,  to  analytical  chemistry 
to  furnish  chemical  descriptions  with  special  precision,  and  this 
is  a  service  promoting  independent  chemical  work.  As  a  mere 
changeful  body  of  directions,  giving  the  latest  expedients  in 
methods,  analytical  chemistry  cannot  claim  to  have  educational 
value.  But  as  an  operative  introduction  to  the  character  and 
deportment  of  compounds,  analysis  becomes  a  logical  mode  of 
study,  fruitful  of  important  results. 

For  certain  common  carbon  compounds  it  has  been  under- 
taken to  furnish  in  this  work,  first,  systematic  chemical  description, 
and  thereupon  the  methods  of  analytical  procedure,  qualitative, 
quantitative,  and  for  proofs  of  purity,  all  with  liberal  citations 
of  the  authorities  for  convenience  of  further  reading.  In  the 
references  an  order  is  observed  as  follows  :  (1)  name  of  the  con- 
tributor, (2)  year  of  the  contribution,  (3)  volume  and  page,  first 
of  original  and  then  of  contemporary  publications. 

Respecting  the  assumed  peculiarities  of  organic  analysis,  it 
more  and  more  appears  that  the  differences  between  inorganic 
and  organic  analysis  have  been  greatly  overstated,  just  as,  at 
earlier  periods,  the  distinction  between  inorganic  and  organic 
chemistry  in  general  was  overdrawn.  With  nearer  acquaintance 
it  is  seen  that  the  limits  of  error  in  determination  of  carbon 
compounds  are  by  no  means  always  wider  than  those  in  analysis 
of  metallic  bodies. 


vi  PREFACE, 

If  the  author  of  this  work  have  done  anything  at  all  to  rescue 
the  analytical  chemistry  of  carbon  compounds  from  a  disjointed 
position  in  chemical  literature,  he  will  have  gained  enough  of 
recompense.  He  desires  to  make*  thankful  acknowledgment  of 
the  encouraging  favor  which  has  been  extended  to  his  "  Outlines 
of  Proximate  Organic  Analysis"  since  its  issue  in  1874.  While 
his  own  promise  of  further  publication  has  waited  long  for  ful- 
filment, works  of  distinct  value  have  opportunely  appeared  in 
different  parts  of  the  same  field,  and  the  flow  of  good  contribu- 
tions has  continued  to  increase  everywhere.  Organic  analysis,  as 
the  determination  of  the  unbroken  compounds  of  carbon,  no 
longer  has  an  uncertain  place  in  chemical  learning. 

ALBERT  B.  PKESCOTT. 

UNIVERSITY  OF  MICHIGAN,  ANN  ARBOR, 
October,  1887. 


ORGANIC    ANALYSIS. 


ABSINTHIN.  C20H28O4 .  H2O=350.— The  neutral  princi- 
ple of  the  wormwood,  Artemisia  absinthium.  Obtained  by  pre- 
cipitating the  hot-water  extract  of  the  leaves  and  tops  by  tannic 
acid,  drying  the  precipitate  with  litharge,  and  extracting  with 
alcohol.  The  absinthin  may  be  purified  by  filtering  the  alcoholic 
solution  through  animal  charcoal,  evaporating,  and  redissolving 
in  ether. 

Absinthin  solidifies  from  yellow  drops  to  indistinct  crystals, 
melting  at  120°  C.,  and  decomposing  at  higher  temperatures.  It 
has  an  aromatic  odor  and  a  very  bitter  taste.  It  is  almost  in- 
soluble in  cold  water,  slightly  soluble  in  hot  water,  freely  soluble 
in  alcohol  or  ether ;  soluble  with  a  brown-red  color  in  the  alkali 
hydrates.  The  potassa  solution,  when  acidified  by  hydro- 
chloric acid,  exhibits  a  yellow-green  play  of  colors. — Concentrat- 
ed sulphuric  acid  dissolves  it  with  brown  color  changing  to 
green-blue,  and  becoming  dark  blue  on  adding  a  very  little  water. 
Much  water  decolors  it.  If  the  alcoholic  solution  be  treated 
with  an  equal  volume  of  concentrated  sulphuric  acid  a  brown - 
red  mixture  results,  and  a  violet  color  is  obtained  after  adding  a 
few  drops  of  water. — Froehde's  reagent  gives  a  brown  color 
changing  to  green  and  violet  (BACH,  1874). — Absinthin  precipi- 
tates mercurous  nitrate  dirty-yellow ;  lead  subacetate  brown  - 
yellow ;  barium  acetate  brown. — Soiling  with  dilute  acids  de- 
composes absinthin  without  producing  a  glucose.  Fehling's  so- 
lution is  not  reduced  by  it :  ammoniacal  s'ilver  nitrate  solution 
is  reduced,  with  the  formation  of  a  mirror. 

ACETIC  ACID.— Essigsaure.  Acide  acetique.  C2H4O2= 
60.  Methyl-carboxyl,  CH3 .  CO2H.  Manufactured  from  alcohol 
or  dilute  alcoholic  liquids  by  oxidation,  or  the  acetous  "  fermen- 
tation," and  from  wood  by  destructive  distillation  yielding  other 
products  of  value.  It  is  produced  in  numerous  chemical  re- 
actions. 

Acetic  acid  is  identified  by  its  odor  in  the  free  state  (b]  and 
the  more  intense  odor  of  its  ethyl  ester  (d).  The  empyreuma  of 


8  ACETIC  ACID. 

heated  acetates  is  characteristic  (d).  It  gives  a  distinctive  color 
with  ferric  salts  (d).  It  is  separated  by  distillation,  if  necessary 
preceded  by  saponification  (e).  From  buty rates,  by  the  insolu- 
bility of  the  barium  acetate  in  alcohol  (Butyric  acid,  e).  It  is 
estimated,  as  free  acid,  by  acidimetry  (f),  or  gravimetric  satura- 
tion ;  as  alkali  acetate,  by  the  alkalimetry  of  the  ignited  residue 
(f).  In  Acetate  of  Lime  by  distillation  and  by  special  methods 
(p.  11).  Commercial  Grades  and  Impurities,  p.  14.  Vinegar, 
its  standards  of  strength,  impurities,  and  special  tests,  p.  15. 

a. — Absolute  acetic  acid  (Glacial  Acetic  acid,  Eisessig)  below 
about  15°  C.  is  a  crystalline  solid,  forming  transparent  tabular 
masses,  melting  at  16.7°  C.  to  a  colorless  liquid*  An  acid  of  87 
per  cent,  melts  below  0°  C. ;  of  62  per  cent,  at  —24°  C.  The 
absolute  acid  boils  at  118°  C.  It  has,  at  15°  C.,  the  sp.  gr.  1.0607 
(water  at  4°  C.)  (MENDELEJEFF). 

b. — Acetic  acid  has  a  pure  acidulous  taste  and  a  penetrating, 
vinegar-like  odor.  When  concentrated  it  is  an  irritant  to  the 
skin  or  tongue,  and  should  be  diluted  before  tasting. 

c. — Acetic  acid  is  soluble  in  all  proportions  of  water  and 
alcohol ;  the  absolute  acid  is  soluble  in  all  proportions  of  ether, 
and  acts  as  a  solvent  for  various  essential  oils,  resins,  camphors, 
phenols,  and  metallic  salts.  Diluted  with  water  acetic  acid  gives 
an  acid  reaction  with  litmus.  The  metallic  normal  acetates  are 
soluble  in  water ;  silver  and  mercurous  acetates  less  freely  than 
the  others.  Perfectly  normal  alkali  acetates  are  neutral  in  re- 
action, a*s  shown  by  phenol-phthalein  or  litmus,  but  potassium 
acetate  is  liable  to  be  found  alkaline,  because  slightly  basic. 
Acetates  in  general  lose  acetic  acid  in  hot  solution,  and  in  some 
instances  by  simple  exposure,  so  that  acetates  exhale  a  percep- 
tible acetous  odor,  and  gradually  become  basic,  o^on-alkali  ace- 
tates, in  solution,  become  slightly  turbid,  by  formation  of  car- 
bonate, from  carbon  dioxide  of  the  air. 

d. — Ferric  chloride  or  other  ferric  salt,  added  not  in  ex- 
cess to  solution  of  acetates,  causes  a  red  color  by  formation  of 
ferric  acetate.  On  boiling,  a  yellow-brown  precipitate  of  basic 
acetate  of  iron  is  obtained,  resolved  finally  into  nearly  pure  ferric 
hydrate.  The  red  liquid,  before  heating,  is  not  decolored  by 
adding  mercuric  chloride  solution,  nor  taken  up  by  shaking  with 
ether,  both  these  negative  results  giving  distinction  from  Thio- 
cyanic  acid.  The  color  is  destroyed  by  adding  sulphuric  or 
hydrochloric  acid — a  distinction  from  Meconic  acid. — By  hot 
digestion  with  sulphuric  acid  and  alcohol,  ethyl  acetate,  or 


ACETIC  ACID.  9 

acetic  ether,  is  formed,  recognized  by  its  penetrating,  fragrant 
odor.  This  test  is  most  efficient  when  the  dry  acetate,  obtained 
from  acidulous  liquid  by  neutralizing  with  fixed  alkali  and  eva- 
porating, is  treated  with  an  equal  quantity  of  alcohol  and  a 
double  quantity  of  sulphuric  acid,  and  heated  or  distilled.  The 
odor  of  other  ethyl  esters  is  liable  to  be  mistaken  for  this. — When 
dry  acetates  are  strongly  heated  in  a  test-tube,  carbon  is  separated 
and  acetone,  CgHgO,  is  evolved,  capable  of  recognition  by  its 
odor. — By  distillation  of  acetates  with  phosphoric  or  sulphuric 
acid,  free  acetic  acid  is  obtained,  with  its  characteristic  odor. — 
Acetic  acid  is  a  stable  compound,  not  oxidized  by  chromic  acid 
nor  by  permanganates.  c 

e.  — Separations.  —  Aqueous  solutions  of  acetates,  if  kept 
slightly  alkaline  with  fixed  alkali,  can  be  concentrated  without 
loss  of  acetic  acid.  The  free  acid  distils  very  slowly,  and  its 
quantitative  distillation  requires  thorough  treatment.  In  distil- 
ling from  acetates,  phosphoric  or  sulphuric  acid,  or  oxalic  aci$,  is 
to  be  added,  in  some  excess  of  the  quantity  needful  to  form  nor- 
mal salts  with  all  the  bases  present.  To  obtain  all  the  acetic  acid 
it  is  necessary  to  distil  to  dryness,  adding  water  and  repeating 
several  times,  until  the  distillate  ceases  to  be  acid  to  litmus. 
When  various  organic  matters  are  present,  it  is  therefore  usually 
better  to  displace  with  phosphoric  acid,  avoiding  the  action  of 
sulphuric  acid  in  distilling  to  dryness.  Care  is  to  be  taken  that 
the  phosphoric  acid  is  strictly  free  from  volatile  acids,  and  that 
salts  of  volatile  acids  other  than  acetic  are  not  present.  If  hy- 
drochloric acid  or  its  salts  are  present,  the  addition  of  sufficient 
silver  sulphate  insures  the  retention  of  the  chlorine.  Further 
details  respecting  quantitative  distillation  are  given  under  f. 

To  obtain  the  acetic  acid  of  basic  acetates  insoluble  in  water, 
it  is  preferable  to  transpose  them  to  alkali  acetate  by  digesting 
with  hot  solution  of  sodium  carbonate,  filtering,  and  exhausting 
with  hot  water.  The  same  operation  may  with  advantage  pre- 
cede distillation  in  the  case  of  lead  acetate.  Ethereal  acetates, 
such  as  ethyl  acetate,  do  not  give  up  their  acetic  acid  by  displac- 
ing it  with  a  non-volatile  acid,  but  require  first  to  be  saponified 
by  an  alkali,  when  the  alkali  acetate  is  treated  as  before  de- 
scribed. The  saponification  is  effected  by  digesting  with  some 
excess  of  a  solution  of  potassa  in  alcohol  free  from  acetic  acid, 
when  all  the  alcohol  may  be  removed  by  evaporation.  Also,  a 
volumetric  estimation  of  the  acetic  acid  of  ethereal  acetates  may 
be  readily  and  exactly  made  by  saponifying  with  a  known  quan- 
tity of  alcoholic  potassa  (see/"). 


io  ACETIC  ACID. 

f.  —  Quantitative. — In  simple  dilution  with  water,  the  spe- 
cific gravity  of  acetic  acid,  if  closely  taken,  is  a  practicable  indi- 
cation of  percentage,  according  to  tables  of  accepted  authority, 
bearing  in  mind  that  acid  of  about  46  per  cent,  coincides  in 
density  with  acid  of  99  per  cent.  Even  within  the  range  to 
which  it  applies,  the  hydrometer  is  not  exact  enough,  unless  cor- 
rected in  its  reading  by  the  analyst  himself. — Saturation  methods 
of  estimation  are  to  be  preferred,  especially  that  by  voliimetric 
solution  of  fixed  alkali.  Phenol-phthalein  is  the  best  indicator, 
but  litmus  will  serve.  Colored  liquids  may  be  diluted  so  as  to 
show  the  phenol  phthalein  indication.  If  6.000  grams  of  the 
acid  mixture  jbe  taken,  each  c.c.  of  normal  solution  of  alkali  indi- 
cates 1  per  cent,  of  C2H4O2,  or  real  acid  ;  each  c  c.  of  decinor- 
mal  alkali,  0.1  per  cent.  With  dilute  acetic  acid,  24.0  grams  may 
be  taken,  when  c.c.  -f-  4  =  %.  But,  owing  to  the  vaporization  of 
acetic  acid,  it  is  seldom  advisable  to  take  a  stated  weight  for  esti- 
mation. In  a  stoppered  bottle,  previously  tared,  pour  5  to  6  c.c. 
of  the  acid  under  estimation,  stopper,  take  the  weight,  and  titrate ; 
grams  taken  :  6.000  ::  c.c.  of  normal  alkali  :  a?  =  per  cent,  real 
acid. 

Gravimetric  methods  of  saturation  may  be  employed.    1.000 

tram  of  potassium  'bicarbonate  (or  0.530  gram  dry  sodium  car- 
onate),  taken  in  a  tall  beaker,  may  be  neutralized  with  the  acetic 
acid,  the  acid  being  added  by  weight  from  a  small,  light,  lipped 
beaker,  carrying  a  small  glass  rod  with  which  to  pour,  adding  at 
last  drop  by  drop,  and  heating  to  expel  the  carbon  dioxide. 
Then  60  -f-  grams  of  acid  required  =  number  per  cent,  of  real 
acid  present.  Before  testing  the  acetic  acid,  if  much  stronger 
than  vinegar,  it  should  be  diluted,  by  weight,  to  from  2  to  15 
times  its  own  weight,  so. as  not  to  be  over  5  to  Si  strength. 
Then  60  X  the  factor  of  dilution  (2  to  15)-r-nurnber  grams  of  the 
diluted  acid  required  =  per  cent,  of  real  acid  present. — A  gravi- 
metric method  with  barium  carbonate  is  as  follows  :  A  weighed 
quantity  of  the  acetic  acid  (sufficient  to  contain  0.120  to  0.180 
gram  absolute  acetic  acid)  is  digested  with  excess  of  well-washed, 
precipitated  barium  carbonate,  the  precipitate  is  filtered  and  ex- 
hausted with  hot  water,  the  filtrate  is  precipitated  by  dilute  sul- 
phuric acid,  with  heating  and  washing  as  required  in  estimation 
of  barium  as  sulphate,  and  the  ignited  barium  sulphate  weighed. 
(BaSO4  :  2C2H4O2 : :  232.8  :  120 : :  1  :  0.5156.)  Grams  of  barium 
sulphate X  0.5156  =  grams  acetic  acid  absolute,  in  the  quantity 
of  acetic  acid  mixture  under  estimation.  Free  acids  which  form 
insoluble  barium  salts  do  not  interfere.  Oxalic  acid  will  add  by 
a  trifling  quantity  to  the  result.  Free  acids  which  form  soluble 


ACETATE   OF  LIME.  II 

barium  salts  interfere  altogether,  but  the  addition  of  sufficient 
silver  sulphate  prevents  interference  of  hydrochloric  acid.  Ace- 
tates and  other  salts  of  non-alkali  metals  precipitable  by  barium 
carbonate  cannot  be  present. 

The  acetic  acid  of  alkali  and  alkaline  earth  salts  may  bo 
estimated  by  ignition  of  the  dry  salt,  and  titration  of  the  result- 
ing alkali  carbonate,  or  alkaline  earth,  with  volumetric  acid. 
Each  c.c.  of  normal  solution  of  acid  used  indicates  0.06  gram  of 
absolute  acetic  acid.  Of  course  the  acetate  taken  for  estimation 
in  this  way  must  be  of  neutral  reaction  ;  or,  if  of  alkaline  reac- 
tion, its  alkalinity  (before  ignition)  must  be  estimated  by  titration, 
and  the  c.c.  of  acid  so  used  must  be  deducted  from  the  c.c.  re- 
quired in  titrating  the  ignited  residue  from  an  equal  quantity  of 
the  salt.  This  plan  of  estimation  is  not  among  the  more  trust- 
worthy ones. 

The  acetic  acid  of  normal  acetates  of  calcium,  lead,  and 
other  non-alkali  metals,  is  sometimes  estimated  by  methods  of 
determination  of  the  metal. 

Valuation  of  "Acetate  of  Lime" — Acetate  of  Lime  (Pyro- 
lignate  of  Lime,  Essigsauren  Kalk,  Holzessigsauren  Kalk)  is  a 
product  of  the  distillation  of  wood,  used  as  a  carrier  of  acetic 
acid  toward  concentration  and  purification.  Its  value  lies  in  the 
amount  of  real  acetic  acid  it  contains.  Three  grades  of  it  have 
been  made — the  a  gray,"  "brown. "and  "  black  " —but  the  last- 
txained  grade  is  now  seldom  produced.  Besides  empyreumatic 
a. id  carbonaceous  matters,  it  is  quite  liable  to  contain  butyrate, 
formate,  and  propionate ; 1  also  magnesium  salts ;  and  may  con- 
tain chlorides.  In  the  plan  of  wood  distillation  conducted  at 
temperatures  below  charring,2  Acetate  of  Sodium  is  usually 
manufactured  instead  of  lime  acetate,  and  no  empyreumatic 
matter  occurs. — In  the  valuation  of  acetate  of  lime,  the  methods 
mostly  in  use  have  been  based  on  (1)  distillation  of  the  acetic 
acid,  and  (2)  the  amount  of  soluble  lime  salts  present.  A  volu- 
metric method  (3)  with  evaporation  of  the  acetic  acid  will  also 
be  given  here.3  The  valuation  should  embrace  an  estimation  of 
the  moisture,  and  may  present  the  proportion  of  magnesium  ace- 
tate, if  any  be  present.  Samples  are  to  be  taken  from  every 

1  Respecting  the  relation  of  these  impurities  to   methods  of  estimation, 
LUCK,  1871  :  Zeitsch.  anal  Chem.,  10,  184. 

2  MABERY,  1883  :  Am.  Chem.  Jour.,  5,  256. 

3  Respecting  methods  (1)  and  (2) — STILLWELL  and  GLADDING,  1882  :  Jour. 
Amtr.   Chem.  Soc..  4,  94.     SEELY,  1872  :  Am.   Chem.,  2,  324  ;  3,  8.     FRESE- 
NIUS,  1875  :  Zeitsch.  anal  Chem.,  14,  172  ;  1866  :  Ibid.,  5,  315  ;  1874  :  Ibid., 
13,  153.     H.  ENDEMANN,  1876  :  Am.  Chem.,  6,  294.     A.  A.  BLAIR,  1885  :  Am. 
Chem.  Jour.,  7,  26. 


12  ACETIC  ACID. 

fifth  to  tenth  bag,  fairly  representing  both  large  and  small  pieces, 
and  inclosed  in  rubber  bags  or  air-tight  jars  while  sent  and  held 
for  analysis.  The  moisture  is  always  to  be  determined  in  a 
portion  taken  as  soon  as  the  sample  is  opened  to  the  air.  The 
sample  is  then  pulverized  and  sifted  in  preparation  for  the  ana- 
lysis. Then  a  prepared  portion  taken  parallel  with  that  sub- 
jected to  analysis  is  dried  for  estimation  of  its  moisture,  from 
which  the  percentage  of  acetic  acid  is  at  last  corrected  for  mois- 
ture, whether  for  the  figures  on  a  dry  basis,  or  on  the  air-dry 
basis  of  the  primary  samples  (Stillwell  and  Gladding).  Crystal- 
lized acetate  of  calcium  contains  water  of  crystallization  and  is 
efflorescent ;  the  product  "  acetate  of  lime  "  may  gain  or  lose 
water  in  the  air^  but  in  paper  or  wood  packages  it  is  likely  to 
lose. 

(1)  By  distillation  of  the  acetic  acid.     The  most  trustworthy 
method.     Of  the  prepared  sample  5  grams  are  dissolved  in  50 
c.c.  of  water,  at  least   25   grams  of  glacial  phosphoric  acid  are 
added,  and  the  liquid  distilled,  repeatedly  adding  water,  not  per- 
mitting the  liquid  to  be  reduced  to  dryness,  and  persisting  until 
the  distillate  ceases  to  have  an  acid  reaction,  or  the  retort  to 
smell  of  acetic  acid.     According  to  Messrs.  Stillwell  and  Glad- 
ding, if  the  retorted   liquid  be  not  reduced  too  low,  not  more 
than  traces  of  hydrochloric  acid  can  be  carried  over  from  chlo- 
rides, and  the  excess  of  phosphoric  acid  prevents  production  of 
insoluble  calcium  phosphate.     All  distillation    of   hydrochloric 
acid  can  be  prevented  by  adding  silver  sulphate  in  the  retort. 
Nitric  acid  must  be  tested  for.    Fresenius  (1875)  and  Endemann 
(1876)  describe  apparatus  by  which  steam  is  introduced  into  the 
retort,  in  a  current  of  regulated  force,  for  continuing  the  distilla- 
tion.    The  total  distillate  is  made  to  a  desired  definite  volume, 
an  aliquot  part  is  measured  out,  phenol-phthalein  added  as  an 
indicator,  and  titrated  with  standard  solution  of  alkali  (p.  10). 

(2)  Methods  depending  on  the  quantity  of  soluble  lime  salts 
present.     Of  these  methods  the  one  given  by  Fresenius  (1874, 
where  cited)  is  one  of  the  best,  and  is  adapted  to  the  assay  of 
pure  grades,  free  from  acid  empyreuma  and  from  magnesium 
salt.     Of  the  sample  5  grams  are  treated  with  about  150  c.c.  of 
water  in  a  quarter-liter  flask,  70  to  80  c.c. -of  normal  solution  of 
oxalic  acid  added,  and  the  mixture  diluted  with  water  to  the  250 
c.c.  mark.     To  compensate  for  the  volume  of  the  precipitate  2.1 
c  c.  of  water  are  added  above  the  mark.    After  being  shaken  and 
standing  for  some  time  the  precipitate  is  filtered  out  (through  a 
dry  filter).      Of  the  filtrate  100  c.c.  are  titrated   with   normal 


ACETATE   OF- LIME.  13 

solution  of  alkali  for  acid  as  acetic  acid.  Then  another  portion 
of  100  c.c.  is  treated  with  calcium  acetate  to  precipitate  all  the 
excess  of  oxalic  acid.  The  calcium  oxalate  precipitate  is  filtered 
out,  washed,  dried,  ignited,  weighed  as  calcium  carbonate,  and 
the  indicated  quantity  of  oxalic  acid  calculated  into  its  equiva- 
lent of  acetic  acid.  The  total  acid  as  acetic  acid  in  ]  00  c.c., 
minus  the  oxalic  acid  as  acetic  acid  in  100  c.c.,  equals  the  true 
acetic  acid  in  100  c.c.  of  •  filtrate — that  is,  in  f  of  the  sample  as- 
sayed (or  in  2  grams). 

(3)  A  method  proposed  by  GOBEL'  is  given  as  follows  :  For 
the  titrations  a  solution  of  soda,  of  which  1000  c.c.  =.  100  grams 
absolute  acetic  acid ;  a  solution  of  phosphoric  acid  which  titrates 
to  phenol-phthalein  of  a  strength  equal  to  the  soda  solution ;  and 
a  solution  of  hydrochloric  acid  which  titrates  to  litmus  of  a 
strength  equal  to  the  soda  solution.  A  weighed  quantity  of  the 
acetate  under  assay  is  treated  with  some  measured  quantity  taken 
as  an  excess  of  the  standard  phosphoric  acid  ;  the  mixture  evapo- 
rated to  dryness  ;  the  residue  treated  with  water  and  evaporated 
again,  and  until  the  odor  of  acetic  acid  is  no  longer  obtained ; 
the  residue  then  treated  with  water  and  the  mixture  titrated  for 
excess  of  phosphoric  acid,  with  the  standard  soda,  using  phenol- 
phthalein,  and  noting  the  result  in  equivalent  of  acetic  acid. 
Subtracting  this  figure  from  that  for  the  acetic  acid  represented 
by  the  phosphoric  acid  first  added,  the  difference  is  the  figure 
for  the  acetic  acid  in  the  acetate  taken — subject,  however,  to  cor- 
rection for  free  lime  and  lime  carbonate  in  acetate  of  lime  taken 
for  assay.  By  titrating  a  weighed  portion  with  the  standard 
hydrochloric  acid,  adding  an  excess,  expelling  carbon  dioxide, 
and  bringing  back  to  the  neutral  tint  of  litmus  with  standard 
soda,  the  acetic  acid  equivalent  to  the  unsaturated  earthy  bases 
is  found,  and  deducted  for  the  correction. 

A  rapid  method  of  assay,  "which  has  been  much  used,  but  is 
apt  to  give  figures  too  high,  is  carried  as  follows :  A  weighed 
quantity  of  the  acetate  of  lime  is  supersaturated  with  a  known 
quantity  of  sodium  carbonate  in  solution ;  the  precipitate  filtered 
out  and  washed ;  and  the  alkali  of  the  total  filtrate  estimated 
as  sodium  carbonate  by  titration  of  an  aliquot  part.  The  loss  of 
sodium  carbonate  due  to  the  removal  of  acetic  acid  (and  acid 
empyreuma)  in  the  precipitation  is  calculated  into  acetic  acid, 
and  figured  upon  the  quantity  of  acetate  of  lime  taken. — BLAIR 
(1885,  where  cited)  obviates  the  difficulty  of  the  color  of  the 

1  1884  :  Repert. '/.  anal.  Chem.,  3,  374  ;  Zeitsch.  anal  Chem.,  23,  264. 


H  ACETIC  ACID. 

solution  by  filtering  it  through  animal  charcoal,  and  then  obtains 
good  results  by  this  method. 

g. — Commercial  Grades  and  Common  Impurities. — The 
strengths  of  acetic  acid  have  been  designated  by  a  "  No.,"  alto- 
gether different  from  vinegar  numbers,  but  probably  originating, 
under  the  British  excise  system,  in  the  number  of  parts  of  four 
per  cent,  vinegar  producible  by  dilution.1  Thus  No.  8  acid  is 
that  which  diluted  to  eight  parts  will  have  about  four  per  cent, 
strength.  The  two  grades  numbered  on  this  system,  in  this  coun- 
try, are  "  No.  8 "  and  "  No.  12."  Interpreted  according  to 
original  intent,  therefore,  No.  8  should  be  of  32  per  cent., 
and  No.  12  of  48  per  cent,  strength.  Dr.  Squibb  finds  that 
the  best  qualities  of  No.  8  acid  actually  prove  of  near  30$ 
strength,  bearing  label  mark  of  s.g.  1.040  ;  the  poorer  qualities 
of  No.  8  are  near  25$  strength,  and  issued  without  a  gravity 
mark.  No.  12  acid  is  less  common,  and  often  runs  from  38  to 
40  per  cent,  of  real  acid. — The  strengths  of  vinegar  numbers 
refer,  in  the  British  custom,  to  the  number  of  grains  of  dried 
sodium  carbonate  neutralized  by  one  Imperial  fiuid-ounce. 
pTagCOg  :  C2H4O2 : :  53  :  60 : :  1  :  1.132.  The  number  x  1.132 
=  grains  absolute  acid  per  fluid-ounce  (of  grains  437.5  X  s-g-) 
The  number  X  0.259  =  grams  absolute  acid  in  100  c.c.  vine- 
gar.— In  this  country  vinegar  numbers  have  been  grains  of 
sodium  bicarbonate  neutralized  by  one  fluid  ounce,  wine  mea- 
sure. NaHCO3  :  C2H4O2 : :  84  :  60 : :  1  :  0.7143.  The  number  x 
0.7143  =  grains  absolute  acid  per  fluid-ounce  (of  grains  455.7  X 
s.g.)  The  number  X  0.1567  '=  grams  absolute  acid  in  100  c.c. 
vinegar. 

Much  of  the  "  Glacial  Acetic  Acid  "  of  commerce  is  not  over 
75  per  cent,  of  real  acid  (SQUIBB).  It  can  easily  be  furnished  of 
99-)-  per  cent.,  as  required  by  U.  S.  Ph. 

Of  impurities  in  ordinary  acetic  acid,  the  more  common  are 
mineral  acids,  especially  hydrochloric,  empyreumatic  bodies,  and 
metallic  salts.  Empyreuma,  and  other  foreign  bodies  having 
odor  or  taste,  are  recognized  by  these  senses  after  neutralizing 
with  potassa  or  soda.  "  When  diluted  with  five  volumes  of 
distilled  water,  the  color  caused  by  the  addition  of  a  few  drops 
of  test-solution  of  permanganate  of  potassium  should  not  be 
sensibly  changed  by  standing  five  minutes  at  the  ordinary  tem- 
perature (absence  of  empyreumatic  substances)." — U.  S.  Ph. 
According  to  Dr.  Squibb,0  when  1  c.c.  of  the  acid,  diluted  with  5 

1  SQUIBB,  1883  :  Ephemeris,  i,  258.  2  1883  :  Ephemeris,  I,  260. 


VINEGAR.  15 

c.c.  distilled  water,  is  treated  with  3  drops  of  decinormal  solu- 
tion of  permanganate,  in  comparison  with  the  same  addition  to 
the  distilled  water,  if  the  color  does  "  not  become  fully  brown  " 
within  ten  minutes,  it  is  "  a  very  good  acid  indeed,"  but  the 
glacial  acid  "  should  stand  this  modification  of  the  permanga- 
nate test  for  more  than  an  hour." 

In  vinegar  the  most  common  impurities  are  (1)  free  mineral 
acids,  and  (2)  empyreumatic  bodies  (in  "  wood  vinegar ").  Be- 
sides, various  made-up  vinegars,  and  forms  of  diluted  acetic  acid, 
are  substituted  for  or  added  to  cider-vinegar. 

The  absence  of  free  mineral  acid  is  shown  by  an  alkaline  re- 
action of  the  ash.  Let  the  residue  be  carefully  ignited  and  the 
cold  ash  touched  with  wet  litmus-paper.  The  residue  can  be 
ignited  on  the  loop  of  platinum  wire.  All  natural  vinegars  con- 
tain some  alkali  acetate,  and  in  absence  of  mineral  acids  will  give 
an  alkaline  reaction  in  the  ash.  If  tl»e  vinegar  be  a  mere  diluted 
acetic  acid,  as  a  "  white  vinegar,"  a  few  drops  of  decinormal 
solution  of  fixed  alkali  are  to  be  added  before  the  evaporation, 
when  a  neutral  reaction  of  the  ash  indicates  free  mineral  acid. — 
To  estimate  the  quantity  of  free  mineral  acid,  take  50  grams  of 
the  vinegar,  add  of  decinormal  alkali  from  the  burette  enough  to 
surely  neutralize  all  free  mineral  acid,  still  leaving  the  reaction 
acidulous,  evaporate,  ignite  with  care  against  loss,  and  titrate 
back  with  decinormal  acid.  Then  c.c.  -^  alkali  —  c.c.  -^  acid 
X 2x0. 0049  —  per  cent,  of  free  mineral  acid,  as  sulphuric  acid. 
IJsing  the  factor  0.00364,  the  statement  is  obtained  for  hydro- 
chloric acid,  etc.  Free  sulphuric  acid,  in  absence  of  chlorides, 
may  be  separated  and  determined  as  follows  :  100  c.c.  are  evapo- 
rated on  the  water-bath  nearly  to  dryness,  treated  with  about  100 
c.c.  of  alcohol,  the  mixture  filtered,  the  alcohol  evaporated  off, 
and  the  residue  diluted  for  the  gravimetric  estimation  of  the 
sulphuric  acid  in  it,  by  precipitation  with  barium  chloride.  If 
chlorides  be  present  in  the  vinegar,  it  is  necessary  to  add  silver 
sulphate  before  adding  the  alcohol,  when  both  the  free  sulphuric 
and  hydrochloric  acids  of  the  vinegar  are  estimated  as  sulphuric 
acid. 

It  must  be  remembered  that  sulphates  and  chlorides  are  liable 
to  be  present  in  legitimate  vinegars,  and  the  simple  reactions 
with  silver  and  barium,  as  prescribed  for  acetic  acid,  are  not 
applicable  in  tests  of  vinegars  in  general.  But,  according  to 
DAVENPORT/  "  in  a  pure  cider  vinegar,  nitrate  of  silver,  nitrate 

1  "  Report  of  Inspector  of  Vinegar  of  the  City  of  Boston,"  1884,  p.  4  ;  of 
Inspector  of  Milk  of  the  same,  1885,  p.  10. 


1 6  ACETIC  ACID. 

of  barium,  or  oxalate  of  ammonium  added  after  an  excess  of  am- 
monia water,  will  neither  of  them  give  more  than  the  slightest 
perceptible  reaction."  Also,  "  a  drop  of  it  in  a  loop  of  platinum 
wire,  when  ignited  in  a  Bunsen  lamp-flame,  gives  a  pure  potash 
flame  without  any  yellow  soda  rays  visible."  "The  addition  of 
any  practical  amount  of  a  commercial  acetic  acid  to  tone  up  the 
strength  will  give  another  color  to  the  flame."  Cider-vinegars 
yield  a  residue  "  always  soft,  viscid,  mucilaginous,  of  apple 
flavor,  somewhat  acid  and  astringent  to  the  taste."  "  If  any 
corn  glucose  is  present,  the  residue,  when  ignited  in  the  platinum 
loop,  will  emit  the  characteristic  odor  of  burning  corn ;  and  if 
the  glucose  was  manufactured  with  the  commercial  sulphuric 
acid  derived  from  copper-pyrites,  it  will,  as  the  last  spark  glows 
through  the  carbonized  mass,  emit  the  familiar  garlic  odor  of 
arsenic."  The  percentage  of  solids  in  cider-vinegar,  by  weight 
of  residue,  is  generally  required  to  be  as  much  as  1.5  per  cent. 
Dr.  DAVENPORT  (1885)  recommends  that  the  legal  limit  be  2 
per  cent. 

"  When  20  grams  of  the  vinegar  are  mixed  with  0.5  c.c.  of 
barium  nitrate  test-solution  (1  to  19)  and  1  c.c.  decinorrnal  silver 
nitrate  solution,  the  filtrate  from  the  mixture  should  give  no  re- 
action for  chlorine  or  sulphuric  acid.  When  two  volumes  are 
added  to  one  volume  of  sulphuric  acid  and  then  one  volume  of 
ferrous  sulphate  solution  poured  over,  no  brown  zone  should 
appear  between  the  layers.  The  evaporation-residue  from  100 
grams  should  riot  exceed  1. 5  grams.  The  residue  should  not  have 
a  sharp  taste,  and  its  ash  should  have  an  alkaline  reaction." — 
Ph.  Germ. 

The  required  strength  of  vinegars  is  given  by  U.  S.  Ph.  of 
1870  at  4.6$;  Br.  Ph.,  5.41#;  Ph.  Germ.,  6$;  the  "proof 
vinegar"  of  British  Excise,  6$,  or  English  "No.  24."  In  exe- 
cution of  the  British  law  against  adulterations  of  foods,  the 
minimum  limit  of  strength  has  been  held  at  3$.  For  "  cider- 
vinegar,"  the  limit  recommended  by  Dr.  Davenport,  in  the  Bos- 
ton City  inspection,  is  5  per  cent,  of  real  acetic  acid ;  and  the 
lowest  limit  there  proposed,  4£  per  cent. — In  New  York  City 
the  legal  requirement,  well  enforced  (1886),  is  4^  per  cent,  of 
acetic  acid  as  a  minimum  for  all  vinegars,  and  2  per  cent,  of 
solids  for  cider- vinegars. 

The  following  is  the  form  of  Inspector's  Record  and  Analyst's 
Report,  under  the  regulations  of  the  city  of  Boston,  1886 : 

"  Vinegar  :  Date,  —  —  ;  Time, ;  Proprietor's  name,  -  —  ; 

No.  — , Street ;  Sold  by ;  Price  paid,  -  — ;  Quan- 
tity,   pint ;  Wholesaler's  name, ;  Price  paid  ditto, ; 


ACONITE  ALKALOIDS.  17 

District, ;  Cider, ;  White  wine,  -    —  ;    How  marked. 

Analysis :    Analysis   No.  -     — ;    Acetic   acid,  -     — ;   Residue, 

— ;  Character  of  residue, ;    Chlorine,  -     — ;    Sulphates, 

• ;  Calcium^ ;  Color, ;  Free  acid." 

ACIDS  OF    THE    FATTY  SERIES,  CnH2nO2.     See 

FATS. 

ACONITE  ALKALOIDS.— Natural  alkaloids  of  plants 
of  the  genus  Aconite  (Ranunculacese),  and  artificial  products 
of  these  alkaloids — represented  bj  Aconitine,  C33H43]TO13  =  645 
(WEIGHT,  1877). 

CONTENTS  : — Chemical  constitution  ;  saponification  changes  ;  list  of  alka- 
loids with  rational  formulae  ;  dehydration  changes  ;  list  of  alkaloids  with  phy- 
siological effects;  sources;  yield.  Analytical  outline  for  crystallizable  and  for 
amorphous  alkaloids  of  aconite  :  a,  heat-reactions  of  each  ;  b,  taste  and  phy- 
siological effects  ;  c,  solubilities  ;  d,  qualitative  tests,  with  limits  ;  e,  separa- 
tion in  general,  from  aconite  root,  from  animal  tissues;  /,  quantitative  methods, 
gravimetric,  volumetric,  of  produced  benzoic  acid  ;  g,  commercial  grades  and 
values. 

Chemical  constitution  and  character. — It  has  been  established 
by  "Wright  and  his  co-workers *  that  the  crystallizable  alkaloids 
of  the  aconite  group  are  salts,  or  esters,  of  benzoic  acid  (or  a 
derivative  of  this  acid),  and  are  readily  saponifiable  ~by  action  of 
alkalies  or  strong  acids,  to  some  extent  even  by  water  with 
heat.  And  the  saponitication  results  in  the  removal  of  either 
benzoic  acid  or  a  derivative  of  benzoic  acid,  and  the  formation  of 
amorphous  alkaloids  in  place  of  the  crystallizable  alkaloids  sapo- 
nified. The  tendency  of  aconite  alkaloids  to  become  amorphous, 
with  diminished  physiological  activity,  is  explained  by  saponifica- 
tion. x  Their  liability  to  another  and  less  obvious  class  of  chemi- 
cal changes,  leaving  them  still  crystallizable  and  with  little  loss 
of  physiological  activity,  is  shown  by  the  proof  that,  l>y  action 
of  strong  acids,  they  suffer  dehydration  and  form  apo- alkaloids. 
That  is  to  say,  alkalies,  with  more  or  less  readiness,  and  even  hot 
digestion  with  water,  cause  saponification;  and  strong  mineral 
acids,  even  concentrated  organic  acids  in  a  degree,  cause  both 
saponification  and  dehydration  to  apo-compounds.2  Various 

1  C.  R.  A.WRIGHT,  in  part  with  A.  P.  LUFF,  and  with  A.  E.  MENKE,  1877- 
1879  :  Jour.  Chem.  Soc.,  31,  143  ;    33,  151,  318  ;  35,  387,  399.     Phar.  Jour. 
Trans.  [3]  8,  164-167.      Further,  MANDELIN,  1885  :   Archiv  d.  Phar.  [3]  26, 
97,  129,  161 ;  Phar.  Jour.   Trans.  [3]  15.      JUERGENS,  1885  :  Phar.  Zeitsch. 
Russland. 

2  It  is  a  noteworthy  correspondence  that  three  active  alkaloidal  agencies  of 
intense  physiological  power,  in  eytensive  medicinal  use  at  present,  Aconitine, 


i8  ACONITE  ALKALOIDS. 

other  transformations  are  brought  about  by  agents  not  so  com- 
monly employed  in  processes  of  separation  as  are  the  alkalies 
and  acids. 

The  following  equations  show  the  changes  of  saponifioation, 
by  alkalies  or  acids,  upon  four  of  the  crystallizable  alkaloids  of 
the  aconites  according  to  Wright : 1 

Crystallizable  alkaloids.  Amorphous  alkaloids.        Benzoic  acid. 

C33H43NO12  (acomtine)+H2O=C26H39NOn  (aconine)+C7H6O2 

(picraconitine)-]-H2O 

=C24H41NO9  (picraconine-f-C7H6O2 

1  (japaconitine)-f-3H2O 

=  2C26H41NO10  (japaconine)+2C7H6O2 

(pseudaconitine)-}- H2O 

Dimethylprotocatechuic  acid. 
= C27H41]SrO9  (pseudaconine )+  C9H10O4 

The  rational  formulae a  of  these  alkaloids  include  the  an- 
hydride of  benzoic  acid,  or  of  one  of  its  derivatives,  in  the 
crystallizable  members  of  the  group ;  and  include  hydroxyl 
instead  of  the  acid  anhydride  in  the  amorphous  members  of  the 
group  (WEIGHT)  ;  as  follows : 

Aconitine,  C33H43NO12=C26H35NO7(OH)3 . 0 .  (C7H5O) 
Aconine,  C26H39NOn = C26H351STO7  (OH)3 ,  OH 
Japaconitine,  C^H^O,-,  =2 [C06H39NO7O . O . (C7H5O)] 0 
Japaconine,  C96H41NO;o=C26H39~lSTO7O .  (OH)2 
Pseudaconitine,3  C36H49NO12=C27H37NO5(OH)3 . 0 .  (C9H9O3) 
Pseudaconine,  C27il41lS[O9=C27H37]NO5(OH)3 .  OH. 

Atropine,  and  Cocaine,  agree  in  being  saponifiable  alkaloids  easily  giving  up 
either  benzoic  acid  or  some  near  derivative  of  benzoic  acid.  (Atropine : 
KRAUT,  1865.  Cocaine  :  LOSSEN,  1865.  Aconitine  :  WRIGHT,  1877.)  Among 
other  saponifiable  alkaloids,  yielding  acids  of  the  aromatic  group,  are  piperine, 
and  certain  veratrum  alkaloids. 

1  In  saponiiication  by  alkali,  the  benzoin  acid  or  its  derivative  is  left  in  com- 
bination with  the  alkali,  from  which  it  is  obtained  by  acidulation.     In  saponi- 
fication  by  acid  the  amorphous  alkaloid  is  obtained  in  salt  of  the  acid. 

2  WRIGHT  (1879),  in   his  last  contribution    upon    the   aconite   alkaloids, 
strongly  inferred  the  existence  of  a  "hypothetical  parent-base,  C33H47NOi2" 
=C26H39N07.(OH)3.0.(C7H50).     JUERGENS  (1885,  where  before  quoted),  by  a 
modified  process  of  extraction  from  the  root,  and  thorough  purification,   ob- 
tained   aconitine    which,    in    elementary    analysis,    gave    him    numbers    for 
C33H47NO]2.      The  alkaloid  gave   the  intense  numbing  sensation  upon  the 
tongue,  without  a  recognizable  bitter  taste. 

3  MANDELIN  (1885),  by  investigations  (without  elementary  analysis),  con- 
cluded that  aconine  and  pseudaconine  are  the  same,  so  that,  in  his  view,  aconi- 
tine and  pseudaconitine  differ  only  by  their  acidulous  radicals  as  found  by 
Wright. 


ACONITE  ALKALOIDS. 


The  amorphous  alkaloids  are  found  in  the  plant,  as  well  as 
obtained  by  alteration  of  the  crystallizable  alkaloids  during  sepa- 
ration from  the  plant. 

The  changes  of  dehydration  to  apo-alkaloids,  by  action  of 
acids,  is  shown  by  the  following  comparisons  of  rational  for- 
mulae : 

Aconitine,  C33H43NO12=C06H35:NO7  (OH)3  .  0  .  (C7H5O) 
Apo-aconitine,  C33H41]SrO11^C26H35NO7  (OH)O  .  O  .  (C7H5O) 

Aconine,  C26H39NO11=C26H35^O7(OH)3  .  OH 
Apo-aconine,  C26H37NO10=C26H35NO7  (OH)2O 

Pseudaconitine,  C3QH:49^O:Lf>^C27}I37NO5  (OH)3.  0.  (C9H9O3) 
Apo  pseudaconitine,  ^30^4^0^ 

=C27H37N06  (OH)0  .  0  .  (C9H903) 

The  natural  alkaloid,  japaconitine,  has  the  constitution  of  a 
sesqui-apo-derivative. 

Chief  Sources  of  the  Natural  Aconite  Alkaloids. 

A.  Naellus*  root.    uAco-        Aconitine. 

Aconine. 

Pseudaconitine  )  in  small  propor- 
Pseudaconine     \      tiori,  if  at  all. 


nite"  of  U.    S.  Ph.  and 
Ph.  Germ. 


A.  ferox,  root.  "  Indian 
Aconite "  "  Nepal  Aco- 
nite." Bish,  or  Bikh. 
"  Himalaya  root." 

Japanese  aconite,  root. 


A.  lycoctonum?  root. 

A.  anthora,  root. 

A.  paniculatum,  root. 


Pseudaconitine. 
Pseudaconine. 


Japaconitine. 
Japaconine. 
Other  alkaloids. 

Aconitine. 
Pseudaconitine. 
Amorph.  alkaloids. 

Pseudaconitine, 
Amorph.  alkaloids. 

Picraconitine. 


1  A  report  of  alkaloids  from  this 
getic  effect  like  curare  —  DRAGENDORFF 


plant,  amorphous,  and  having  an  ener- 
& SPOHN,  1884. 


2O 


ACONITE  ALKALOIDS. 


The  chief  Aconite  Alkaloids  :  Synonyms,  Crystallization,  and 

Activity. 


'       Name. 

Synonyms. 

Formula. 

Crystallization. 

Physiolog.  effect. 

Aconitine. 

Cryst.  aconitine. 
Napaconitine. 

C33H43N012 

Crystallizable, 
when    free, 
as  well  as  in 

salts. 

Of  typical  aco- 
nite activi- 
ty. 

Pseudaconitine. 

Napelline. 
t^eraconitine. 
Acraconitine. 
English  aeon. 

C36H49N012 

Base    and    its 
salts     crys- 
tallize  with 
difficulty. 

Approaches  to 
or  equals  the 
activity  of 
aconitine. 

Japaconitine. 

Cryst.  alkaloid  of 
Japanese  root. 

Ce.H88N.O,, 

Crystallizable 
both       free 
and  in  salts. 

Closely  resem- 
bles aconi- 
tine in  pro- 
perties and 
effects. 

Aconine. 

Amorphous  aco- 
nitine. A  pro- 
duct of  aconi- 
tine, by  alkalies 
or  acids. 

C26H39NOn 

Amorphous, 
both       free 
and  in  salts. 

./  s 

Of  far  low- 
er activity 
than  aconi- 
tine. Bitter. 

Pseudaconine. 

Amorphous    aco- 
nitine.    A  pro 
duct  of   pseud- 
aconitine,      by 
alkalies. 

C27H41N09 

Amorphous, 
free  or  com 
bined. 

Of     far    low 
•  er     activity 
than   acorn 
tine.  Bitter. 

Japaconine. 

Amorphous  alka- 
loid of  Jap. 
aconite.  Pro- 
duct of  Japaco- 
nitine. 

C26H41N010 

Amorphous, 
free  or  com- 
bined. 

Closely  resem- 
bles aeon  in  e 
in  properties 
and  effects. 

Picraconitine. 

Inactive,  bitter  al- 
kaloid of  A.  pa- 
niculatum  and 
other  species. 

C3iH45N010 

Base       crvst. 
with      diffi- 
culty.  Salts 
crystallize 
well. 

Bitter.        Not 

poisonous. 

Picraconine. 

Amorphous  pro- 
duct of  picraeo- 
nitine. 

C24H41N09 

Amorphous. 

Bitter.  Not 
poisonous. 

Apo-aconitine. 

Product  of  aconi- 
tine, by  action 
of  acids. 

C33H41N011 

Crystallizable. 

Of    the    same 

activity  as 
aconitine. 

Corresponding  apo-derivatives,  by  action  of  acids  on  Pseudaconitine,  Aconine, 

etc.     (See  p.  19.) 


ACONITE   ALKALOIDS.  21 

For  medicinal  uses  the  II.  S.  Ph.  and  Ph.  Germ,  admit  only 
the  tuberous  root  of  A.  Napellus ;  the  Br.  Ph.,  also  U.  S.  Ph.  of 
1870,  admit  both  "  root  "  and  leaf  of  A.  Napellus  ;  the  Ph.  Fran, 
authorizes  the  use  of  root  and  leaf  of  A.  Napellus  and  A.  ferox. 
It  is  understood  that  both  Japanese  aconite  root l  and  root  of  A. 
ferox  are  largely  used  for  the  manufacture  of  medicinal  alkaloid 
"aconitine."  A.  Sterkeanum  contains  poisonous  alkaloids. 

Yield  of  natural  Aconite  Alkaloids. — WRIGHT  obtained,  in 
1876,  from  A.  Napellus  only  0.03  per  cent,  of  pure  aconitine, 
and  only  0.07  per  cent,  of  total  alkaloids  free  from  other  matter. 
Again,  from  Japanese  aconite  roots  0.18  per  cent,  of  mixed  al- 
kaloids. JUERGENS  (1885)  obtained,  by  a  modified  Duquesnel's 
process,  of  thoroughly  purified  aconitine  (for  elementary  analy- 
sis) 0.02  per  cent.  By  chemical  assays  (1883)  LABOKDE  and 
DUQUESNEL  found  in  A.  Napellus  root,  of  "  crystalline  alkaloids  " 
from  0.05  to  0.40  per  cent.,  averaging  0.15  per  cent. ;  of  "  amor- 
phous, insoluble  substance  "  having  an  effect  like  aconitine  in 
kind,  "a  few"  tenths  per  cent.;  and  of  "  amorphous,  soluble,  bit- 
ter substance,"  about  1.5  per  cent.  ZINOFFSKI,"  working  by  volu- 
metric estimation  with  Mayer's  solution  (probably  an  inexact 
measure  of  total  aconite  alkaloids)  in  A.  Napellus  and  other 
species,  from  the  fresh  leaf  (calculated  to  basis  of  dry  material) 
0.73  to  1.38  per  cent,  total  alkaloid  ;  from  the  fresh  stalks,  0.25 
to  0.90  per  cent. ;  and  from  the  fresh  flowers,  1.51,  1.65,  and 
5.52  (!)  per  cent,  total  alkaloids.  HAGER  (1863)  reported  fi nd- 
ing  in  the  best  commercial  root  of  A.  Napellus  from  0.64  to  1.25 
per  cent,  [total  alkaloids].  SQUIBB  (1882)  found  the  leaf  of  A. 
Napellus  to  have  only  about  one-ninth  of  the  physiological  effect 
of  the  same  quantity  of  the  root.  CULLAMORE  (1884)  found  the 
action  of  A.  ferox  to  be  more  intense  in  degree  than  that  of  an 
equal  quantity  of  A.  Napellus. 

The  "  aconitine  "  of  the  market  may  contain  any  mixture  of 
the  aconite  alkaloids — frequently  aconitine,  japaconitine,  pseud- 
aconitine,  and  the  wholly  amorphous  alkaloids.  Systematic  phy- 
siological assay  of  four  commercial  grades  of  "  aconitine,"  by  Dr. 
SQUIBB  in  1882,  in  comparison  with  good  powdered  aconite  root, 
gave  the  following  results  :  (1)  Of  unknown  make  had  only  the 
physiological  potency  of  the  root ;  (2)  "  Ordinary,"  8  times  the 
strength  of  the  same  weight  of  the  root ;  (3)  Pseudaconitine,  83 
times  the  power  of  the  root ;  (4)  "  Crystallized,"  111  times  the 

1  Respecting  Japanese  and  Chinese  Aconites,  see  LANGGARD,  also  WASO- 
vicz,  1880  :  Archiv    d.  Phar.,  14,  217,  and  15,  161  ;  Phar.  Jour.  Trans.,  [3] 
10,  149,  1020  ;  Proc.  Am.  Pharm.,  29,  170-182. 

2  Dragendorff's  "  Werlhbestimmung,"  1874,  p.  13. 


22  ACONITE  ALKALOIDS. 

effect  of  the  root.  If  we  accept  Wright's  analyses,  first  above 
given,  the  total  aconite  alkaloids  should  have  from  500  to  1400 
times  the  potency  of  the  same  weight  of  root.  Further,  Dr. 
Squibb  found  that  the  article  (4)  was  a  nitrate  containing  not 
more  than  80.7  per  cent,  of  hydrated  alkaloid.  Aconitine  was 
dropped  in  the  last  revision  of  the  U.  S.  Ph.  and  in  the  last  re- 
vision of  the  Ph.  Germ.  It  is  retained  by  Br.  Ph.  and  Ph.  Fran. 

THE  CRYSTALLIZABLE  ACONITE  ALKALOIDS  are  identified  by 
their  organoleptic  effect  (b),  the  agreement  of  their  precipitations 
(d9  p.  25)  and  solubilities  (c),  and  by  yielding  benzoic  acid  or  its 
derivative  when  saponified  (p.  18,  and  under  j).  THE  AMORPHOUS 
ALKALOIDS  of  the  aconites  are  distinguished  from  the  crystalliz- 
able  ones  by  greater  solubilities  in  water  (<?),  greater  reducing 
power  (d),  greater  bitterness  without  lip-tingling  effect  (5),  and 
by  not  yielding  benzoic  acid  or  its  derivative  when  saponified 
(under/1).  Aside  from  sources  and  accompaniments,  amorphous 
aconite  alkaloids  are,  with  difficulty,  identified  by  a  general  agree- 
ment of  precipitations  (d),  solubilities  (b),  and  melting  points  (d). 
Aconite  alkaloids  are  separated  from  the  aconite  roots,  indeter- 
minate matters,  etc.,  by  assay  processes  of  extraction  (e) ;  from 
tissues,  etc.,  in  analyses  for  poisons  in  the  body  as  directed, 
with  procedure  for  identification  (under  e).  The  active  alkaloids 
are  separated  by  crystallization.  The  total  alkaloids  of  aconite 
are  estimated  gravimetrically,  or  volumetrically  (f).  Separate 
estimation  of  the  active  alkaloids  is  proposed,  by  saponification 
and  determination  of  the  quantity  of  benzoic  acid  and  veratric 
acid  (f).  For  practical  estimation  of  active  alkaloids  alone,  by 
physiological  assay,  under  J,  p.  23.  For  commercial  grades  and 
values,  fj  sources,  p.  19. 

a. — Aconitine  crystallizes  anhydrous  in  rhombic  or  hexa- 
gonal tables,  appearing  in  snow-white  flakes;  and  its  salts  crystal- 
lize well.  Japaconitine  crystallizes  well,  both  free  and  in  its 
salts.  Pseudaconitine  and  its  salts  do  not  crystallize  without 
very  careful  treatment ;  from  ether,  or  better  a  mixture  of  ether 
with  petroleum  benzin,  it  forms  needles  or  sandy  crystals,  with 
1  ag.,  but  unless  the  concentration  be  extremely  slow  only  cau- 
liflower-like efflorescence  or  a  varnish  layer  will  be  obtained. 
The  nitrate  crystallizes  when  treated  with  care.  Picraconitine 
crystallizes  with  difficulty  as  a  base ;  its  salts  easily  form  good 
crystals.  Aconine,pseudaconine,  and  japaconine,  with  their  salts, 
are  white,  powdery  solids,  strictly  uncrystallizable.  The  apo- 
alkaloids  agree  in  crystallization  with  the  aconite  alkaloids  from 


ACONITE  ALKALOIDS.  23 

which  they  are  formed — apo-aconitine  being  crystallizable,  and 
.apo-aconine  amorphous.  The  Br.  Ph.  describes  "  aconitine  "  as 
"  a  white,  usually  amorphous  solid  "  ;  the  Ph.  Fran,  as  "  colorless 
rhombic  tables."  As  found  in  the  shops,  "  aconitine "  (mixed 
alkaloid)  is  usually  amorphous,  often  colored,  sometimes  in  thin, 
partly  effloresced  plates,  sometimes  in  large  needles. 

Aconitine  melts  at  18-i0  C.  (WRIGHT)  ;  pseudaconitine  loses 
water  of  crystallization  at  80°  C.,  melts  at  105°  0.,  and  de- 
composes at  about  130°  C.  ;  japawnitine  melts  at  184°  to 
186°  C. ;  'ac&nine  melts  at  130°  C. ;  pseudaconine  at  100°  C. ; 
picraconitine  does  not  melt  on  the  water-bath ;  apo-aconitine 
melts  at  185°  C.  These  alkaloids  all  preserve  a  constant  weight 
on  the  water-bath ;  when  ignited  they  burn  away  slowly.  As  to 
sublimation,  and  microscopic  identification  of  the  sublimate,  see 
HELWIG  (1864) '  and  BLYTH  (1878).2 

J. — Acomtine,  in  solutions  dilute  enough  to  be  safe  for  the 
trial,  causes  a  tingling  and  characteristic  numbness  of  the  lip 
and  tongue  and  pharynx,  commencing  after  a  delay  of  from  a 
minute  to  a  quarter  of  an  hour,  according  to  the  extent  of  dilu- 
tion. Dr.  SQUIBBS  found  that  0.006  gram  (0.1  grain)  of  good 
.aconite  root,  in  a  solution  of  3.7  c.c.,  or  1  fluid-drachm  (of  its 
soluble  constituents),  held  in  the  anterior  part  of  the  mouth  (pre- 
viously rinsed)  for  sixty  seconds,  and  then  discharged,  gave  the 
tingling  sensation  (as  a  rule),  commencing  within  15  minutes 
:and  then  continuing  for  a  quarter  or  a  half  an  hour.  When  the 
same  volume  of  solution  was  made  to  contain  the  soluble  part  of 
0.02  gram  (0.3  grain)  of  the  root,  the  tingling  began  in  5  to  10 
minutes,  increased  for  a  time,  and  continued  in  all  about  1.5 
hours.  If  we  accept  the  percentages  of  total  alkaloid  reported 
by  Wright  (0.07  to  0.18$),  and  grant  the  entire  alkaloid  to. have 
the  full  activity  of  aconitine,  then,  on  the  foregoing  data,4  from 
•0.000004  to  0.00001  gram  (0.00006  to  0.00015  grain)  of  this  alka- 
loid in  a  fluid-drachm  of  solution  held  one  minute  in  the  mouth 
•causes  lip- tingling  within  a  quarter  of  an  hour.6  But  this  de- 

1  Zeitsch.  anal.  Chem.,  3,  52.  2  Jour.  Chem.  Soc.,  33,  316. 

3 1882  :  Ephem&ris,  I,  125. 

4  It  appears  safe  to  assume  that  the  specific  action  of  the  aconites  is  repre- 
sented by  their  alkaloids.  FLEMING  found  aconitic  acid  to  have  little  effect 
upon  rabbits  when  subcutaneously  injected.  TORSELLINI  (1884)  reported  aconi- 
tic acid  to  have  a  paralyzing  effect  on  the  heart  of  a  frog. 

6  "  The  physiological  action  of  aconitine  is  excessively  energetic,  so  much 
so  as  to  render  working  with  it  a  matter  of  considerable  pain  and  difficulty, 
unless  great  care  be  taken  in  the  manipulation,  and  more  especially  in  avoid- 
ing the  dust  of  the  crystals  of  the  base  or  its  salts.  A  minute  fragment,  too 
small  to  be  seen,  if  accidentally  blown  into  the  eye,  sets  up  the  most  painful 


24  ACONITE  ALKALOIDS. 

gree  of  potency  is  not  attained  by  commercial  "aconitine." — 
Aconitine  is  commonly  described  as  having  a  bitter  taste,  which,, 
in  proportion  to  its  special  activity,  is  not  at  all  pronounced. 
JUERGENS  (1885)  found  carefully-purified  aconitine  to  have  no 
recognizable  bitterness.  The  bitterness  of  commercial  "  aconi- 
tine "  is  in  inverse  ratio  to  its  purity,  in  freedom  from  amor- 
phous aconite  alkaloids. 

The  medicinal  dose  of  absolute  aconitine  orpseudaconitineioY 
a  man  is  placed  by  MANDELIN  (1885)  at  0.0001  gram  (-g^  grain) 
in  a  single  dose,  and  0.0005  (^  grain)  during  24  hours. 
Of  Duquesnel's  "aconitine"  SEQUIN  (1878)  gave  0.0005  gram 
(TST  gram)  as  a  single  full  dose  ;  and  the  same  quantity  of  Hot- 
-tet's  "  aconitine  "  was  given  as  a  single  maximum  dose  by  GUB- 
LER  (1880).  Of  commercial  crystallized  "aconitine  "  of  unknown 
strength,  current  authorities  limit  the  first  (or  trial)  dose  at  about 
0.0002  gram  (-^Jg-  grain),  but  this  is  double  the  dose  of  absolute 
aconitine  declared  by  Mandelin,  as  above. — The  -  smallest  fatal 
dose  of  absolute  aconitine,  or  pseudaconitine,  for  a  man  is  placed 
by  MANDELIN  (1885)  at  0.003  gram  (near  -^  grain) ;  for  warm- 
blooded animals,  0.00005  to  0.000075  gram  per  kilogram  of  body- 
weight  ;  for  frogs,  0.0012  to  0.0024  gram  per  kilogram  of  body- 
weight.  BLYTH  (1884)  deduces  that,  of  French  aconitine  or 
Morson's  aconitine,  by  the  mouth,  the  least  fatal  dose  for  a  man 
is  0.002  gram  (^  grain),  equal  to  0.000028  gram  per  kilogram 
of  body- weight ;  for  the  cat  0.000075  to  0.00009  gram  per  kilo- 
gram of  body-weight.  With  the  frog  (DRAGENDORFF)  0.002 
gram  [aconite  alkaloid]  causes  paralysis  of  the  hind  legs  in  a  few 
minutes. 

Dilatation  of  the  pupil  is  not  a  constant  effect  of  aconitine, 
but  usually  occurs  in  some  stages  of  its  action. 

Pseudaconitine,  indefinitely  represented  by  the  old  "  napel- 
line,"  undoubtedly  has  nearly  or  quite  the  same  physiological 
effect  as  aconitine.  CULLAMORE  (1884)  found  the  action  of 
Aconitum  f erox  root  to  be  similar  in  kind  to  action  of  A.  !Na- 
pellus. 

The  wholly  amorphous  aconite  alkaloids,  aconine  and  pseud- 
aconine,  have  but  in  a  very  low  degree  the  specific  activity  of 
aconitine.  HUSEMANN  (1884  :  Phar.  Zeituny]  found  aconine  to 
have  a  toxic  effect  on  frogs  and  mice,  an  effect  300  to  400  times 
less  than  that  of  aconitine.  Wright  stated  of  aconine  and  of 

irritation  and  lachrymation,  lasting  for  hours  ;  whilst  similar  particles,  if  in- 
haled, produce  great  bronchial  irritation,  or  profuse  sneezing,  and  considerable 
catarrh  or  '  sore  throat,'  according  to  the  part  where  they  lodge." — C.  R.  A. 
WRIGHT,  first  report. 


ACONITE  ALKALOIDS.  25 

pseudaconine  that  it  is  of  extremely  bitter  taste,  but  does  not  pro- 
duce the  slightest  lip-tingling. 

The  apo-alkaloids  of  aconite  have  the  effect  of  the  alkaloids 
from  which  they  are  derived.  Apo-aconitine  has  the  full  physio- 
logical activity,  and  apo-aconine  is  an  inactive  bitter. 

Picraconitine  is  very  bitter,  and  quite  destitute  of  the  spe- 
cific potency  of  aconitine. 

Aconitine,  and  its  allied  bases,  have  a  decided  alkaline. re- 
action, and  neutralize  acids  perfectly,  forming  salts  more  stable 
than  the  free  alkaloids.  The  nitrate  is  a  favorite  salt  for  crystal- 
lization. 

c. — Aconitine  is  very  little  soluble  in  cold  water  (in  726  parts, 
JUERGENS,  1885),  but  dissolves  in  hot  water,  and  in  alcohol  (24 
parts  of  90$  alcohol),  ether,  benzene  (sparingly  when  cold),  freely 
soluble  in  chloroform,  soluble  in  amylalcohol  (DRAGENDORFF), 
does  not  dissolve  in  petroleum  benzin  or  carbon  disulphide.  It 
requires  2806  parts  of  petroleum  benzin  for  solution  (JUERGENS). 
It  is  not  dissolved  from  aqueous  solutions  of  its  salts  by  ether, 
or  chloroform,  or  benzene. — P seudaconitine  is  sparingly  soluble 
in  water,  more  freely  soluble  in  alcohol  and  in  ether  than  aconi- 
tine is  (WRIGHT).  Japaconitine  is  soluble  in  .alcohol  and  in 
ether  ;  pier  aconitine  is  very  sparingly  soluble .  in  water.  A  co- 
nine  is  freely  soluble  in  water,  alcohol,  or  chloroform,  almost  in- 
soluble in  ether,  especially  when  free  from  alcohol  (WRIGHT). 
Pseudaconine  dissolves  in  water,  or  alcohol,  or  ether  (WRIGHT). 
Apo- aconitine  and  apo-aconine  dissolve  in  ether. 

d. — The  most  delicate  and  distinctive  test  for  the  active  al- 
kaloids of  the  aconites  is  the  physiological  test  for  lip  tingling, 
described  on  p.  23. 

Aconite  alkaloids — namely,  aconitine  and  pseudaconitine — and 
their  amorphous  products,  aconine  and  pseudaconine,  are  precipi- 
tated, from  their  nearly  neutral  solutions  in  hydrochloric  acid, 
as  follows  (WRIGHT)  :  by  "  bromine  water,  iodine  dissolved  in 
potassium  iodide,  tannin,  gold  chloride,  mercuric  iodide  dis- 
solved in  potassium  iodide,  mercuric  bromide  in  potassium  bro- 
mide, and  mercuric  chloride.  These  precipitates  dissolve  on 
more  or  less  largely  diluting  the  fluids,  the  aconine  precipitates 
being  more  soluble  than  the  corresponding  pseudaconine  ones, 
which  again,  save  in  the  case  of  tannin,  are  markedly  more 
soluble  than  those  of  aconitine  or  pseudaconitine.  Other  things 
being  equal,  the  mercuric  chloride  precipitates  are  more  soluble 
than  those  formed  with  mercuric  bromide,  which  are  more  solu- 
ble than  those  thrown  down  by  mercuric  iodide.  Aconine  is 


26  A  CONITE  A  LKA  L  OWS. 

not  precipitated  by  sodium  carbonate  or  ammonia,  save  when 
the  solution  is  evaporated  almost  to  dryness,  so  that  an  oily  liquid 
separates  along  with  the  solid  sodium  or  ammonium  salt  ;  pseud- 
aconine  behaves  similarly,  whilst  aconitine  and  pseudaconitine 
are  but  sparingly  soluble  in  excess  of  these  reagents.  Strong 
caustic  potash  precipitates  all  four  bases,  the  aconitine  and  pseud- 
aconine  precipitates  being  only  sparingly  soluble  in  excess,  the 
pseudaconine  being  much  more  readily  soluble  on  diluting  the 
fluid,  and  aconine  being  precipitated  only  in  very  concentrated 
solutions.  Platinic  chloride  throws  down  precipitates  only  with 
strong  solutions,  especially  with  pseudaconine  and  aconine,  the 
precipitates  in  all  cases  dissolving  readily  on  dilution. — It  is 
noticeable  that  picraconitine  is  scarcely  distinguishable  from 
aconitine  in  these  reactions,  excepting  that  with  sodium  car- 
bonate and  ammonia  it  is  precipitated  much  less  readily,  the 
precipitate  being  formed  only  in  concentrated  solutions,  and  dis- 
solving readily  on  dilution." 

Further  (WEIGHT),  the  amorphous  alkaloids,  aconine  and 
pseudaconine,  are  distinguished  from  the  crystallizable  aconite 
alkaloids  by  greater  reducing  powers — reducing  silver  (slowly) 
from  hot  solution  of  silver  nitrate  or  of  ammoniacal  silver  ni- 
trate ;  and  gold  from  the  gold  chloride  precipitate,  on  standing. 
Aconine  reduces  Fehling'  s  solution  on  boiling,  a  distinction  from 
pseudaconine,  which  does  not. — Both  crystallizable  and  amorphous 
aconite  alkaloids  (like  the  ptomains)  promptly  reduce  f erricyanide 
of  potassium,  as  shown  by  a  drop  of  ferric  salt  solution. 

Limits. — The  precipitation  by  iodine  in  potassium  iodide  is 
distinct  (on  a  glass  slide)  in  one  grain  of  a  solution  of  the  al- 
kaloid in  50,000  times  its  weight  of  water  (WORMLEY).  With 
the  gold  chloride,  one  grain  of  a  solution  of  the  alkaloid  in  5,000 
parts  yields  in  a  little  time  a  quite  fair  precipitate  ;  diluted  to 
20,000  parts,  after  some  time  a  just  perceptible  turbidity.  With 
bromine  in  hydrobromic  acid,  one  grain  of  a  solution  of  one 
part  of  the  alkaloid  in  10,000  parts  of  water  gives  a  quite  fair 
precipitate  (WORMLEY).  The  limit  of  the  precipitation  by  potas- 
sium mercuric  iodide  (DRAGENDORFF)  is  about  0.0009  gram  in 
1  c.c.  of  acidified  solution,  acidulation  diminishing  the  solubility 
of  the  precipitate.  Phosphomolybdic  acid  gives  a  yellow  pre- 
cipitate, changing  to  blue  on  standing,  and  dissolving  blue  in 
ammonia — 0.00007  gram  alkaloid  in  1  c.c.  water  acidulated  with 
sulphuric  acid  giving  a  distinct  precipitate  after  half  an  hour 
(DRAGENDORFF).  1 

1  A  test  for  completely  purified  aconitine  is  given  by  JUEBGENS  (1885)  as 
follows  :  The  particle  of  solid  alkaloid,  or  residue  of  its  solution,  on  a  glass 


ACONITE  ALKALOIDS.  27 

The  color  reactions  by  acids,  Froehde's  reagent,  etc.,  are  so 
widely  varied  by  alterations  and  differences  (impurities)  of  the 
aconite  alkaloids  that  no  dependence  can  be  placed  upon  them, 
unless  the  results  are  interpreted  by  results  of  control  tests  made 
by  the  analyst  upon  strictly  parallel  aconite  products.1 

€< — Separations. — Aconite  alkaloids  are  not  vaporized,  but 
are  very  slowly  saponilied,  by  concentration  of  their  aqueous  so- 
lutions on  the  water-bath.  Such  concentration  should,  if  pos- 
sible, be  done  in  neutral  solution,  and  action  of  alkalies  is  gene- 
rally more  destructive  than  action  of  acids.  Dr.  SQUIBB  stated 
(1882)  that  the  attenuated  solutions  of  aconitine,  and  those  of 
fluid  extract  of  aconite,  diminished  in  strength,  shown  by  physio- 
logical action,  after  the  second  day  ;  and  in  four  days,  the  weather 
being  warm,  they  became  quite  inert,  the  growth  of  cryptogams 
keeping  pace  with  the  loss  of  strength. — Aconite  alkaloids  can 
be  shaken  out  or  extracted  from  slightly  alkaline  (not  from  aci- 
dulous), cold,  aqueous  solutions,  by  ether,  chloroform,  etc.,  ac- 
cording to  the  solubilities  in  these  respective  liquids,  given  on 
p.  25.  And  from  solution  in  these  liquids  acidulated  water  takes 
up  the  alkaloids 

In  separation  from  aconite  root,  the  process  of  Duquesnel, 
modified  by  Wright  and  otherwise  varied  in  details,  well  serves 
the  purpose  of  an  assay.  The  powdered  root  is  percolated  to 
exhaustion  with  alcohol  (not  acidulated)  This  is  done  much  the 
best  by  the  continuous  operation  of  an  extraction  apparatus.  The 
solution  is  concentrated,  preferably  by  boiling  under  reduced 
pressure,  to  remove  the  alcohol,  the  liquid  diluted  with  water 
to  a  limpid  state,  and  just  acidulated  with  tartaric  acid.  One 
part  of  tartaric  acid  to  100  parts  of  the  root  is  the  propor- 
tion of  Duquesnel's  process,  in  which  the  acid  is  added  to  begin 

slide,  is  treated  with  a  drop  of  water  acidulated  with  acetic  acid,  and  a  minute 
fragment  of  potassium  iodide  added,  when  presently  rhombic  tables  appear 
under  microscopic  inspection.  Obtained  with  O.OOOOU5  gram. 

1  When  aconite  is  dissolved  in  hot  phosphoric  acid  previously  fully  concen- 
trated on  the  water-bath,  there  appears,  according  to  the  purity  of  the' alkaloid, 
a,  violet  to  brown  color— at  all  events  crystallized  aconitine  is  but  feebly  colored 
by  tne  phosphoric  acid,  and  crystallized  aconitine  nitrate  is  not  colored  at  all. 
The  yellow  color  by  sulphuric  acid  diminishes  in  the  same  way  (FLUCKIGER'S 
"Pharm.  Chera.,"  1879).  Concentrated  aqueous  phosphoric  acid  dissolves  aconi- 
tine, giving  on  the  water-bath  a  beautiful  violet  color,  remaining  for  a  day  in 
the  cold — a  distinction  from  "pseudaconitine"  (that  is,  "  napelline,"  "  Morson's 
aconitine,"  or  "English  aconitine"),  which  remains  colorless  (HEPPE'S  "Die 
chemischen  Reaction  en,"  1875,  from  HUBSCHMANN,  HASSELT,  HERBST,  PRAAG). 
"I  found  the  color  yellow  at  80°  C.,  reddish  at  89°  C.,  violet  at  133°  C.'?— DRA- 
GENDORFF  in  "Organische  Gifte,"  1872.  JUERGENS  (1885)  obtained  purified 
aconitine  which  gave  no  color  reactions  with  phosphoric  acid,  sulphuric  acid 
and  sugar,  or  phosphomolybdic  acid  and  ammonia. 


28  ACONITE  ALKALOIDS. 

with.     The  liquid  is  now  filtered,  by  help  of  the  filter-pump,, 
and  the  resinous  residue  washed  with  a  little  water.      The  solu- 
tion is  now  washed  several  times  with  ether,  the  total  etherial 
washings  being  washed  with  a  little  water  slightly  acidulated 
with  tartaric  acid,  returning  the  aqueous  washing  to  the  acidu- 
lous solution.     Sodium  carbonate  is  now  added  to  a  clearly  alka- 
line reaction,  and  the  liquid  shaken  out  with  ether  to  complete 
exhaustion.      The  etherial  solution  is  concentrated  in  a  flask  as 
far  as  it  may  be  without  formation  of  residue,  and  then  washed 
several  times  with  water  slightly  acidulated  with  tartaric  acid  ; 
seeing  that  the  reaction  is  distinctly  acid  after  shaking  with  the 
ether.     The  aqueous  liquid  is  at  once  made  barely  alkaline  by 
adding  sodium  carbonate  (if   deemed  advisory,  is  washed  once 
with  light  petroleum  benzin),  and  then  shaken  out  with  ether,  re- 
peatedly, as  before.    The  united  etherial  solution  is  concentrated, 
at  last  spontaneously,  to  crystallize  ;  or  when  partly  concentrated 
a  little  light  petroleum  benzin  is  added  and  the  solution  set  at 
rest  to  concentrate  and  crystallize.     In  either  case  all  resinous 
residues  are  thoroughly  washed  with  ether  by  the  filter-pump, 
and  this  etherial  solution  shaken  out  again  with  acidulated  water, 
made  alkaline,  and  shaken   out  with   ether,  concentrating  this 
solution  to  crystallize  as  before.     The    crude  crystallized  and 
amorphous  alkaloids  may  be  purified  by  repeatedly   dissolving 
them  with  ether,  on  the  filter,  by  the  filter- pump,  and  "  crystal- 
lizing "  again,  to  obtain  the  total  free  alkaloids  for  weight. — Or 
the  crude  crystallized  and  amorphous  alkaloids  are  treated  with  a 
strong  solution  of  sodium  nitrate  at  a  gentle  heat,  and  cooled  for 
crystallization  of  the  nitrates  of  the  alkaloids.     These  may  be 
further  purified  by  treating  their  concentrated  aqueous  solution, 
made  alkaline  by  sodium   carbonate,  with  repeated  portions  of 
chloroform,  to  obtain  all  the  alkaloid,  and  permitting  the  chloro 
formic  solution  to  concentrate  for  crystallization  of  crystallizable 
alkaloids. — It  is  much  better  if  a  "  liquid-extraction  apparatus  " 
be  used  throughout  the  process,  instead  of  "  shaking  out "  by 
many  portions  of  the  solvents.     And  it  is  much  better  to  make 
the  concentrations  promptly,  by  partial  vacuum,  at  temperature 
not  above  60°  C. 

In  separation  from  animal  tissues,  etc..  in  cases  of  possible 
poisoning,  the  same  method,  substantially,  may  be  followed — ex- 
tracting the  neutral  or  neutralized  mixture  with  alcohol,  concen- 
trating, then  acidulating  and  filtering,  as  above  directed.  A  mix- 
ture of  chloroform  and  ether  is  preferred  by  some  analysts,  and 
chloroform  alone  by  others,  as  a  solvent  for  the  extractions.  If 
crystals  are  not  readily  obtained,  the  final  purified  portions  may 


ACONITE  ALKALOIDS.  29 

be  obtained  in  concentrated  neutral  aqueous  solutions  for  de- 
terminative tests.  The  physiological  test  should  be  first,  and 
then  drop  tests  are  to  be  made  upon  a  glass  slide  over  white  or 
black  ground,  under  a  magnifier.  If  the  alkaloids  of  aconite  be 
identified,  a  further  effort  should  be  made  to  obtain  the  crystals. 
The  aconite  alkaloids  have  been  recovered  from  the  liver  and 
other  organs,  from  the  blood,  and  from  the  urine.  Aconitine  was 
detected  by  DRAGENDORFF  in  the  stomach  two  months  and  nine 
days  after  death.1 

f. — Quantitative. — Aconite  alkaloids  may  be  dried  at  100°  C. 
for  gravimetric  determination. — The  gold  salt  of  aconitine  pure 
is  best  dried  over  sulphuric  acid  in  the  dark,  when  a  constant 
weight  at  100°  C.  may  be  rapidly  assured,  and  the  product 
weighed  as  C33H43NO12 .  HC1 .  AuCl3  (WEIGHT).— The  gold  pre- 
cipitate of  the  probably  mixed  aconite  alkaloids  was  found  by 
DRAGENDORFF  to  have  from  25  to  31  per  cent,  of  gold,  as  sepa- 
rated by  warming  with  sulphuric  and  oxalic  acids.3 

Volumetric  estimation  of  (total)  alkaloids  of  the  aconites  are 
made  by  Mayer's  solution — witli  approximate  results — as  follows 
(DRAGENDORFF)  :  The  solution  is  made  (by  a  previous  approxi- 
mate assay)  to  contain  one  part  alkaloids  to  150  or  200  parts  of 
water,  and  slightly  acidulated.  The  end  of  the  reaction  is  found, 
by  filtering  a  drop  or  two,  through  a  very  small  filter,  upon  a  watch- 
glass,  and  adding  a  drop  from  the  burette,  when,  if  turbidity  ap- 
pears, the  watch-glass  and  filter  are  drained  and  rinsed  with  a 
few  drops  of  water  into  the  alkaloidal  solution,  and  another  ad- 
dition made  from  the  burette.  Each  c.c.  of  the  Mayer's  solution 
indicates  0.0274  gram  of  the  alkaloid  (empirical),  the  amount 
to  be  increased  by  0.00005  gram  for  each  c.c.  of  the  total  liquid 
containing  the  precipitate.  The  results  are  near  enough  indica- 
tions of  tiie  quantity  of  total  alkaloids  to  be  practically  useful 
for  commercial  assays  of  aconites  and  their  preparations — pro- 
vided always  that  quantity  of  total  alkaloids  could  serve  a  com- 
mercial purpose  in  absence  of  any  index  of  the  proportion  of 
amorphous  alkaloids. 

A  method  of  estimation  of  the  crystallizable  and  physiologi- 
cally active  alkaloids  was  proposed  by  Mr.  WRIGHT  in  1877,8  to 
be  done  by  saponification,  and  estimation  of  the  resulting  benzoic 

1  For  the  instructive  account  of  analysis  by  Drs.  DUPRE  and  STEVENSON, 
in  the  Lampson  case,  in  London,  in  1882,  see  The  Lancet,  March  18,  1882,  p. 
455  ;  Wharton  and  Stillffs  "  Med.  Juris.,"  vol.  2,  1884,  Phila.  ed.,  p.  634. 

2  "Gerichtl.  Chemie,"  1872,  p.  62. 
3Phar.  Jour.  Trans.,  [3]  8,  164-178. 


30  AGO  N I  TIC  ACID. 


acid,  and  dimethylprotocatechuic  acid  (see  p.  18).  Saponitica- 
tion  is  made  complete  by  boiling  alcoholic  potash,  or  by  water 
with  digestion  at  140°-1500  C.,  in  sealed  tubes.  Distilling  with 
water  separates  the  benzoic  acid  from  the  dimethylprotocateclmic 
acid.  The  weight  of  the  benzoic  acid  is  \  that  of  the  aconitine. 
The  weight  of  the  dimethylprotocateclmic  acid  is  £  that  of  the 
pseudaconitine. 

g. — Commercial  grades  and  values. — An  elaborate  pharma- 
cological valuation  of  several  brands  of  aconitine  was  made, 
using  frogs,  rabbits,  dogs,  and  pigeons,  by  PLTJGGE  in  1882.1  It 
was  determined  that  Petit' s  "  nitrate  of  aconitine ' '  was  eight 
times  stronger  than  Merck's  "  nitrate  of  aconitine,"  and  one  hun- 
dred and  seventy  times  stronger  than  Friedlander's ;  also,  that 
"  German  aconitine  "  is  variable.  Of  the  samples  examined  by 
Plugge  he  found  the  following  order  of  diminishing  strength : 
"  Nitrate  of  aconitine  "  :  (1)  Petit's,  (2)  Morson's,  (3)  Hottet's, 
(4)  Hopkins  and  Williams's  "  pseudaconitine,"  (5)  Merck's  "  aco- 
nitine nitrate,"  (6)  Sclmchardt's  "  aconitine  sulphate,"  (7)  Fried- 
lander's  "  nitrate  of  aconitine."  These  figures  must  not  be  taken 
as  indicating  the  strength  of  all  the  alkaloids  furnished  under 
these  respective  brands.  Dr.  SQUIBB  (p.  23)  found  the  relative 
strength  of  four  articles  to  be,  in  proportion :  Duquesnel's 
"  crystallized  aconitine,"  -111 ;  Merck's  "  aconitine  from  Hima- 
laya root "  (pseudaconitine),  83  ;  Merck's  "  aconitine "  (ordi- 
nary), 8  ;  unknown  "  aconitine,"  1  ;  the  powdered  root  of  A. 
Napellus,  1. — The  "  Aconitine  japonicum  "  of  Merck  claims  to 
be  japaconitine. 

ACONITIC  ACID.  H3C6H3O6  =  174:.—  Found  in  Aconi- 
tum  Napellus  (monks-hood)  and  other  species  of  Aconitum,  in 
Delphinium  Consolida  (larkspur),  in  JEquisetum,  Helleborus 
niger,  Achillea  Millefolium  (yarrow),  Adonis  vernalis,  and 
other  plants.  It  is  a  product  of  citric  acid  by  heat,  and  occurs 
in  various  citric  acid  concentrated  juices  of  commence,  in  sugar- 
cane juice,2  and  in  the  scale  from  sorghum-sugar  pans,3  but  it  is 
not  manufactured  for  use. — Crystallizes  in  white,  warty  masses, 
or  very  slowly  in  four-sided  plates  or  hard  needles.  It  darkens 
at  130°  C.,  melts  at  140°  C.,  and  boils  at  160°  C.,  when  it  gradu- 

1  Archiv  d.  Phar.,  [3]  20 ;  Am.  Jour.  Phar.,  54,  171.     Also,  on  this  ques- 
tion, HARNACK  and  MENNICKE,  1883. 

2  BEHR,  1877:  Deut.  Cliem.  Ges.  Ber.,  10,  351. 

3  H.  B.  PARSONS,  1882  :  Am.  Chem.  Jour.,  4,  39  ;   Jour.  Chem.  Soc.,  42, 


A  CONITINE.—^SCULIN.  3 1 

ally  decomposes  into  Itaconic  acid,  C5H6O4 ,  and  carbon  dioxide. 
Citraconic  anhydride  and  other  pyrocitric  acids  occur  at  higher 
temperature.  Aconitic  acid  is  soluble  in  water,  alcohol,  and 
ether ;  its  solutions  have  a  strongly  acid  reaction,  and  a  purely 
acid  taste.  It  is  tribasic  and  forms  three  classes  of  salts. — Free 
aconitic  acid  solution  is  precipitated  by  solutions  of  niercurous 
nitrate  and  lead  acetate,  and  alkali  aconitates  are  precipitated 
by  lead  nitrate,  silver  nitrate,  and  ferric  chloride  (red-brown). 
Calcium  aconitate  is  only  sparingly  soluble  in  water.  Phos- 
phorus pentachloride,  with  heat,  gives  a  cherry-red  liquid,  de- 
colored by  water.  Nitric  acid  in  boiling  solution  is  deoxidized 
with  evolution  of  brown  vapors. 

Aconitic  acid  is  prepared  from  plants  in  which  it  exists  as 
calcium  salt,  by  evaporating  the  clear  decoction  to  crystallize. 
The  crystals  of  aconitate  of  calcium  are  dissolved  by  slight  acidu- 
lation  with  nitric  acid,  and  precipitated  by  acetate  of  lead,  and 
the  lead  salt  decomposed  by  hydrosulphuric  acid.  The  residue 
of  the  nitrate  is  taken  up  by  ether,  and  the  acid  remaining  on 
evaporation  of  the  ether  is  dissolved  in  water  and  crystallized  in 
vacuum  over  sulphuric  acid.1  It  is  also  separated  from  im- 
purities by  adding  (to  the  dry  mixture)  five  parts  of  absolute 
alcohol,  then  saturating  the  filtered  solution  with  hydrochloric 
acid,  and  adding  water,  when  aconitate  of  ethyl  will  rise  as  an 
oily  layer,  colorless  and  of  aromatic  odor.  This  ether  may  be 
transposed  by  potassium  hydrate. 

Aconitic  acid  may  be  best  obtained,  artificially,  from  citric 
acid.a 

ACONITINE.     See  ACONITE  ALKALOIDS. 

^ESCULIN.  C^Hj.pOgrr:  240  (SCHIFF,  1870 ;  LIEBEKMANN, 
1880). — The  bitter  principle  of  the  bark  of  the  horse-chestnut 
(JEsculus  hippocastanum).  Not  identical  with  gelsemic  acid 
(WORMLEY,  1882).  •  Obtained  by  precipitating  a  decoction  of  the 
bark  with  lead  acetate,  filtering,  and,  after  removing  the  lead 
from  the  filtrate  by  hydric  sulphide,  concentrating  to  a  syrup 
and  allowing  to  crystallize.  It  may  be  purified  by  repeated 
crystallization  from  alcohol  and  finally  from  boiling  water. 

Crystallizes  in  snow-white,  very  small  needles,  arranged  in 

1  BUCHNER:    Pliarm.  Repert.,  63,  145.      A  method   of  separation  from 
Equisetum  was  given  by  BAUP  in  1850  :  Liebig's  Annalen,  77,  293  ;  JaJir.  d. 
Chem.,  1850,  372. 

2  PAWOLLECK,  1876:   with  process,  Liebig's  Annalen,   178,   150;    Jour. 
Chem.  Soc.,  29,375. 


32  ALKALOIDS. 

globular  masses  or  in  the  form  of  fine  powder.  They  have  the 
composition  C15II16O9  2H2O,  and  lose  1JH2O  at  110°  C.,  and  the 
rest  of  the  water  upon  melting  at  160°.  It  is  odorless,  slightly 
bitter,  and  reddens  litmus.  Soluble  in  642  parts  cold  and  12-J- 
parts  boiling  water,  in  about  100  parts  cold  and  24  parts  boiling 
alcohol ;  insoluble  in  absolute,  slightly  soluble  in  ordinary  ether  ; 
soluble  in  dilute  acids  and  alkalies.  The  aqueous  solution  (con- 
taining the  merest  trace  of  the  glucoside)  exhibits  a  distinct  blue 
fluorescence,  which  is  more  marked  if  well-water  is  used,  and  is 
destroyed  by  addition  of  acids.  The  alkaline  solutions  are  yel- 
low, but  exhibit  a  blue  fluorescence.  It  is  dissolved  by  chlorine 
water  with  red  color  which  changes  through  brown-red  to  yellow. 
Nitric  acid  forms  a  yellow  solution  with  it,  which  becomes  red 
upon  addition  of  excess  of  potassium  hydrate.  Boiling  with 
dilute  acids  converts  it  into  cesculetin,  OgllgO^1  and  glucose. 
Ferric  chloride  colors  its  solutions  green.  It  reduces  alkaline 
cupric  solution  upon  boiling.  It  is  not  precipitated  by  any  of 
the  metallic  salts  except  lead  subacetate.  If  a  small  portion  of 
sesculin  be  treated  with  four  drops  of  concentrated  sulphuric 
acid,  and  to  the  slightly  colored  solution  there  be  gradually 
added  a  solution  of  sodium  hypochlorite,  a  bright  violet  colora- 
tion is  obtained  (RABY,  1885). 

ALKALOIDS. — Nitrogenous  carbon- compounds  capable  of 
neutralizing  acids. 

CONTENTS  : — Basal  character  ;  solubilities  in  water,  in  the  immiscible  sol- 
vents, free  and  acidified  ;  extraction  by  solvents  ;  management  of  emulsions  ; 
filtering  out ;  styles  of  "separators"  ;  stoppers;  siphon  for  separators  ;  tests 
of  completed  extraction  ;  the  purity  of  the  immiscible  solvents  ;  liquid-extrac- 
tion apparatuses-;  forces  affecting  solubilities.  Precipitation  by  alkalies  ;  the 
scheme  of  Fresenius  ;  the  "general  reagents"  for  the  alkaloids,  with  the  re- 
covery of  the  alkaloid  from  each — (1)  iodine,  (2)  Mayer's  solution,  volumet- 
ric uses,  (3)  phosphomolybdate,  (4)  bromine,  (5)  cadmium  iodide,  (6)  bismuth, 
(7)  tungsten  compounds,  etc.,  (8)  tannin,  (9)  picric  acid,  (10)  platinic  and  auric 
chlorides  ;  color-reactions,  with  sulphuric  acid  alone  and  the  several  oxidizing 
agents,  cane-sugar,  etc.  ;  Froehde's  reagent ;  nitric  acid  ;  ferric  chloride,  etc. 
Microscopic  methods  ;  microsublimation,  and  "the  subliming  cell." 

In  their  most  obvious  characteristics  these  compounds  are 
mostly  divisible  into  two  classes:  (1)  Non- volatile  Alkaloids,  com- 
pounds of  C,  H,  JsT,  O ;  solids,  melting  and  subliming  usually 
with  partial  decomposition  when  heated.  (2)  Volatile  Alkaloids, 
compounds  of  C,  H,  N" ;  liquids  of  slight  vaporization  at  ordi- 
nary temperatures  and  high  boiling  points.  The  natural  alka- 

1  On  the  constitution  of  assculin  and  aesculetin,  LIEBERMANN,  1880  ;  WILL, 
1883. 


ALKALOIDS.  33 

loids  of  the  first  class  are  far  more  numerous  than  those  of  the 
second  class. 

Both  classes  mostly  include  bodies  of  decided  basic  power ; 
of  an  alkaline  reaction  restricted  by  sparing  aqueous  solubility ; 
bases  neutralizing  acids  in  the  production  of  their  salts,  which 
crystallize  in  characteristic  forms  of  a  good  degree  of  perma- 
nence. 

In  water  the  free  alkaloids  have  generally  little  solubility, 
but  their  sulphates,  nitrates,  hydrochlorides,  and  acetates  mostly 
dissolve  with  abundance  in  this  vehicle.  In  alcohol  the  free 
alkaloids  dissolve  in  most  cases  with  moderate  abundance,  and 
their  common  salts  almost  invariably  dissolve  largely. 

In  the  solvents  immiscible  with  water — ether,  chloroform, 
benzene,  petroleum  benzin,  arnyl  alcohol,  etc. — the  free  alkaloids 
differ  among  each  other  as  to  their  solubilities,  which  thus  be- 
come important  means  of  separation.  The  salts  of  the  alka- 
loids are,  with  some  important  exceptions,  insoluble  in  the  sol- 
vents immiscible  with  water.  Separations  of  alkaloids  soluble 
in  a  liquid  not  miscible  with  water,  from  other  substances  soluble 
in  the  same  menstruum,  are,  therefore,  accomplished  by  first 
washing  the  acidulated  aqueous  solution  to  remove  whatever 
non-alkaloidal  matter  is  soluble  in  the  applied  menstruum,  and 
then  washing  the  alkaline  aqueous  liquid  to  take  out  the  alkaloid 
itself.1  Then,  again,  the  non- aqueous  (etherial)  solution  of  the 
free  alkaloid  may  be  washed  with  acidulated  water,  when  a  salt 
of  the  alkaloid  is  formed  and  transferred  to  the  aqueous  liquid, 
as  a  step  in  separation. 

The  washing  of  the  aqueous  liquid  with  a  solvent  immiscible 
with  water,  sometimes  designated  as  the  shaking  out,  is  com- 
monly done  by  agitating  in  a  cylindrical  stoppered  vessel  (Fig.  1, 
p.  35),  and  leaving  the  mixture  at  rest  for  the  immiscible  sol- 

1  This  mode  of  using  ether  was  proposed  in  1856  by  OTTO,  in  modification 
of  STAS'S  process  for  the  recovery  of  alkaloidal  poisons.  The  plan  was  adopted 
for  chloroform  by  RODGERS  and  GIRDWOOD  in  1856  ;  and  for  amyl  alcohol  by 
USLAR  and  ERDMANN  in  1861.  In  1867  DRAGENDORFP  (Phar.  Zeitsch.  f.  Russ- 
land,  6,  Heft  10  ;  Zeitsch.  anal.  Chem.,  7,  521  ;  "Ermittelung  von  Giften," 
St.  Petersburg,  1868,  p.  242)  presented  a  quite  comprehensive  scheme  of  separa- 
tions by  solvents  immiscible  with  water,  applied  both  in  acidulated  and  in  al- 
kaline solutions.  This  scheme  was  translated  by  the  author,  in  ''Outlines  of 
Proximate  Organic  Analysis"  in  1875,  and.  more  in  detail,  by  S.  Dana  Hayes 
(Am.  Chemist,  6,  378)  in  1876.  The  plan  of  separation,  first  published  in  a 
pharmaceutical  journal,  and  primarily  for  the  uses  of  the  toxicologist,  has  been 
extended  by  chemists  everywhere,  so  that  it  is  now  the  most  common  mode  of 
separation  of  alkaloids  for  any  purpose,  in  analysis  or  manufacture.  Moreover, 
the  way  of  ' '  shaking  out "  by  solvents  immiscible  with  water  is  in  frequent  use 
for  fats  and  acids  and  other  bodies  besides  alkaloids. 


34  ALKALOIDS. 

vent  to  separate  in  a  clear  layer,  which  is  then  drawn  off  or  de- 
canted in  some  way.  The  solvent  layer  will  be  over  the  aqueous 
layer  in  the  case  of  the  ordinary  solvents  except  chloroform,  the 
layer  of  which  will  be  under  the  watery  liquid.  A  mixture  of 
one  volume  of  chloroform  witli  three,  or  at  the  least  two,  volumes 
of  ether  is  sometimes  used  as  an  immiscible  solvent,  lighter  than 
water.  Mixtures  of  alcohol  (as  a  solvent)  with  ether,  or  chloro- 
form, or  amyl  alcohol  cannot  be  used  in  "  shaking  out,"  because 
the  water  removes  the  alcohol  from  the  immiscible  liquid.  In. 
fact,  this  liquid  becomes  water- washed  by  the  operation,  and  there 
are  advantages  in  taking  a  water- washed  ether  or  chloroform  to 
begin  with,  so  that  the  disturbing  presence  of  alcohol  (and  pos- 
sibly of  acids)  may  be  avoided.  It  is  to  be  borne  in  mind  that 
ordinary  stronger  ether  contains  4  or  5,  per  cent,  of  alcoholr 
and  ordinary  purified  chloroform  contains  alcohol  not  exceeding 
1  per  cent. ;  also  that  both  these  liquids  are  liable  to  contain,  and 
to  acquire,  free  acids.  It  is  even  possible  that,  in  shaking  out 
with  several  portions  of  acidulous  ether,  the  reaction  of  the  aque- 
ous liquid  may  be  changed  from  alkaline  to  acid,  and  if  this 
change  be  overlooked  the  separation  may  be  reversed  without  the 
knowledge  of  the  operator.  The  absence  of  free  acid,  therefore, 
is  to  be  required  of  ether,  chloroform,  or  amyl  alcohol  when  one 
of  these  is  used  as  a  solvent  upon  an  aqueous  liquid.  Washing 
with  water,  readily  done  by  the  analyst,  serves  to  remove  both 
alcohol  and  acids,1  but  the  removal  of  acids  is  done  sooner  and 
with  less  waste  by  washing  with  alkaline  wrater.  "What  is  said  of 
"  water-washed  "  solvents  by  no  means  applies  to  the  commercial 
article  known  as  "  water-washed  ether,"  which  is  of  low  grade, 
containing  much  alcohol,  a  slight  extent  of  water- washing  being 
substituted  for  other  more  efficient  means  in  its  purification. 

Although  the  presence  of  alcohol  somewhat  lessens  the  sepa- 
rative power  of  the  solvent,  yet  the  addition  of  small  quantities 
of  alcohol  is  sometimes  resorted  to  to  promote  the  formation  of 
a  clear  layer  of  the  immiscible  solvent,  and  (as  a  diluent)  to  resolve 
obstinate  emulsions  which  now  and  then  hinder  the  analyst. 
The  various  resources  for  preventing  and  destroying  emulsions 
are  named  from  time  to  time  in  the  directions  in  this  work. 
The  resolution  of  an  emulsion  into  the  two  clear  layers  of  the 
immiscible  liquids  concerned  is  always  promoted  by  some  degree 
of  miscibility  between  these  liquids,  just  as  a  precipitate  that  has 
some  slight  degree  of  solubility,  or  that  crystallizes,  usually  sub- 

1  The  use  of  water-washed  solvents,  as  standard  grades  of  constant  compo- 
sition, was  proposed  by  the  author  in  1875  (Pro.  Am.  Asso.  Adv.  Sci.,  24,  i., 
114). 


ALKALOIDS.  35 

sides  the  more  readily  to  leave  a  clear  liquid.  Ether  forms  a 
layer  sooner  than  chloroform,  and  benzene  is  liable  to  give  more 
trouble  in  the  formation  of  emulsions  than  either  of  the  former. 
The  operator  will  learn  that  in  most  cases  it  is  better  to  avoid 
the  production  of  an  obstinate  emulsion,  not  shaking  violently 
enough  to  cause  it,  but,  if  necessary,  obtaining  the  desired  contact 
of  the  two  liquids  by  a  slow  and  prolonged  reversing  of  the  upper 
and  lower  ends  of  the  separator.  Precautions  against  emulsions, 
and  devices  for  their  resolution,  are  given  with  the  various  direc- 
tions for  separations  of  Atropine,  Cocaine,  Strychnine,  and  else- 
where in  this  work.  Among  such  measures  may  be  here  enume- 
rated :  (1)  the  application  of  heat  enough  to  cause  a  very  slight 
or  incipient  boiling  of  the  solvent,  or  of  the  water  when  amyl 
alcohol  is  the  solvent ;  (2)  the  introduction  of  small  portions  of 
the  clear  solvent,  with  or  without  clear  water,  through  a  little 
tube,  into  the  intermediary  layer  of  emulsion  ;  (3)  the  addition 
of  a  small  portion  of  the  fresh  solvent,  then  gently  agitated  and 
set  aside  for  separation  of  layers,  this  being  done  either  with  the 
whole  liquid  or  with  the  emulsified  portion  of  the  liquid  drawn 
off  for  the  purpose ;  (4)  the  dilution  of  the  solvent  with  alcohol ; 
(5)  gently  jarring  the  separator  ;  (6)  filtrations. 

The  emulsified  intermediary  layer,  drawn  off  by 
a  siphon  or  pipette,  or,  if  need  be,  the  entire  mixture, 
may  be  filtered,  using  a  double  paper  filter  (with  four 
thicknesses  all  around),  and  wetting  the  filter  with  the 
heavier  of  the  two  constituent  liquids.  That  is,  with 
fresh  chloroform,  if  this  be  solvent ;  with  distilled 
water,  if  the  solvent  be  other  than  chloroform.  The 
first  portion  of  the  filtrate,  or  even  the  whole  of  it, 
may  be  returned  through  the  filter,  and  the  filter  and 
lighter  liquid  remaining  in  it  may  be  washed  with 
successive  small  portions  (or  with  a  fine,  continuous 
stream)  of  the  heavier  liquid. 

As  a  "  separator "  the  author  prefers  one  with  a 
cylindrical  body  and  a  short,  conical  base,  the  exit- 
tube  being  of  small  diameter  and  closed  with  a  stop- 
cock next  to  the  body.  The  stoppered  opening  at 
the  top  of  the  separator  should  be  of  good  width. 
Fig.  1  represents  a  convenient  article,  to  be  held  by 
a  "  condenser  clamp." 

But  instead  of  a  "  separator,"  a  large  test-tube,  or  test-glass 
with  foot,  may  be  used  with  convenience,  if  provided  as  follows : 
The  top  of  this  cylindrical  tube  is  fitted  just  like  that  of  a  wash- 
bottle,  with  a  stopper  bearing  a  delivery-tube  and  blow-tube,  as 


36  ALKALOIDS. 

illustrated  in  Fig.  2.  The  delivery-tube  is  to  be  narrow  i  and 
play  up  and  down  in  the  stopper,  to  take  off  the  liquid  content, 
either  the  upper  or  lower  layer,  at  any  point.  The  blow-tube  is 
so  bent  and  long  enough  to  enable  the  operator  while  blowing 
to  see  clearly  the  movement  of  the  liquid  at  the  inner  end  of 
the  delivery-tube,  when  this  is  brought  near  the  line.  The 
division  between  layers  may  be  carried  to  very  near  the  outer 
end  of  the  delivery-tube,  when  the  remaining  liquid  is  drawn 
back  again.  To  rinse  the  deli  very- tube  the  stopper  is  transferred 
to  a  tube  containing  a  little  of  the  clean  solvent,  which  is  shaken 
up  and  then  blown  out.  To  make  an  exact  separation  of  the 
layers,  a  small  quantity  of  the  fresh  chloroform  or  other  solvent 
may  be  drawn  in  through  the  delivery-tube  of  the  apparatus  last 


above  mentioned,  next  to  the  aqueous  layer,  without  disturbing 
the  layers,  which  are  thus  separated  from  each  other.  In  other 
apparatus  the  introduction  may  be  through  a  pipette. 

Rubber  stoppers  and  tubes  are  acted  on  by  ether  and  chloro- 
form, and  can  only  be  used  when  the  liquid  does  not  come  in 
contact  with  them,  and  then  only  for  a  short  time,  as  they  are 
soon  injured  and  swollen  by  the  vapor  of  these  menstrua.  Good, 


ALKALOIDS.  37 

well-pressed  corks  serve  for  brief  uses  without  special  prepara- 
tion; but  to  avoid  waste  of  vapor  in  standing,  and  especially 
where  the  solvent  is  to  be  distilled,  as  described  hereafter,  the 
corks  should  be  rendered  impervious,  after  being  fitted,  by  an 
application  of  chrome-gelatine.  Four  parts  of  gelatine  are  dis- 
solved in  52  parts  of  boiling  water,  the  solution  filtered,  and  1 
part  of  ammonium  dichromate  added.  This  mixture  is  applied 
as  a  coating  to  the  corks,  and  permanent  cork  connections  may 
be  completely  sealed  by  covering  the  corks  in  place  over  upon 
the  glass.  After  application  the  coating  should  stand  two  days 
in  the  light  to  harden. 

It  will  occur  to  any  analyst  sometimes  to  make  separations 
with  immiscible  solvents,  as  preliminary  trials,  or  as  small  quali- 
tative or  quantitative  tests  of  a  tentative  character,  when  a  test- 
tube  or  vial  is  a  sufficient  container,  and  the  one  liquid  may  be 
drawn  off  from  the  other  with  a  pipette.  In  using  a  mouth 
pipette,  however,  it  is  usually  better  to  take  out  the  aqueous 
layer,  this  being  the  less  volatile  liquid,  and  less  liable  to  drip 
when  the  pipette,  closed  at  the  top,  is  being  withdrawn.  Also 
a  simple  siphon  of  narrow  glass  tubing  bent  in  U-form  may  be 
filled  with  the  solvent  or  with  water,  and  used  to  draw  off  either 
layer  from  any  container. 

In  any  case,  a  separation  by  or  from  an  immiscible  solvent 
is  of  the  nature  of  a  washing,  and  complete  removal  of  the 
dissolved  body  is  not  accomplished  by  a  single  division  into  the 
two  liquid  layers,  or  with  a  single  portion  of  the  solvent.  Suc- 
cessive portions  of  the  solvent  must  be  applied,  in  repetition  of 
the  "  shaking  out."  Especially  is  this  true  with  ether,  chloro- 
form, and  amyl  alcohol,  which  dissolve  in  water  to  some  extent. 
From  two  to  five  washings  may  be  required.  In  any  case  of 
doubt  and  of  importance,  positive  information  must  be  gained  by 
a  test  of  the  last  "  wash-liquid,"  as  in  ordinary  quantitative  analy- 
sis, and  the  washings  repeated  until  the  last  liquid  drawn  off,  or 
the  residue  therefrom,  gives  a  negative  result  under  some  deli- 
cate test  for  the  alkaloid  operated  upon.  In  all  the  cases  where 
assay  operations,  by  a  single  shaking  out  with  (say)  chloroform, 
have  been  verified  by  good  authority  as  giving  a  correct  result 
under  a  control  analysis,  it  may  be  almost  certainly  set  down  that 
the  correctness  of  the  result  lies  in  a  happy  balance  of  errors 
rather  than  in  the  clear  truth.  The  loss  of  the  alkaloid  taken 
is  just  balanced  by  the  gain  of  foreign  matter  which  goes  into 
the  weight  at  the  end.  And  if  all  the  conditions  of  loss  and  of 
gain  can  be  held  constant,  or  nearly  so,  the  method  may  give 
results  of  substantial  correctness. 


ALKALOIDS. 


The  purity  of  the  immiscible  solvents  chosen  for  use  must 
be  assured.  Let  a  good  portion  be  evaporated  to  dryness  in  a 
weighed  beaker,  and  the  absence  of  fixed  residue  ascertained. 
The  residue  may  well  be  taken  up  with  acidulated  water,  and  the 
solution  subjected  to  test  by  some  of  the  "  general  reagents  for 
alkaloids,"  or  by  the  chief  qualitative  test  to  be  used  in  the 
contemplated  analysis.  If  necessary,  the  solvents  are  to  be 
purified  by  distillation. 


To  avoid  the  attenuation  due  to  the  use  of  repeated  portions 
of  solvent,  as  well  as  the  expense  of  considerable  quantities 
of  the  same,  a  plan  of  distillatory  use  of  the  solvent  has  been 
recently  proposed,  in  the  so-called  "  extraction-apparatus  for 
liquids."  This  apparatus  corresponds  in  principle  to  the  ex- 
traction-apparatus of  Tollens  and  others  for  the  continuous  per- 


ALKALOIDS. 


39 


eolation  of  solids,  which  have  been  for  some  years  the  favorite 
means  of  applying  solvents  to  organic  bodies,  and  is  described 
under  Plant  Analysis.  The  immiscible  solvent  is  distilled  from 
its  solution  while  it  is  being  applied,  in  the  apparatus  of  later 
device,  to  the  aqueous  liquid.  The  apparatus  of  SCHWARZ  (1884)1 
is  shown  in  Fig.  3.  It  is  connected  above  with  a  returning  con- 
denser. The  two  connecting  tubes  serve,  the  one  to  carry  vapor 
to  the  condenser,  the  other  to  conduct  the  overflow  of  condensed 
solvent  back  to  the  warmed  reservoir — both  these  tubes  having  a 
mercury-joint  provided  for  by  an  inclosing  cup.  NEUMANN'S 
apparatus 2  will  be  understood  from  Fig.  4.  A.  EILOAKT  (1886)3 
describes  a  simple  apparatus  (Fig.  5)  which  can  be  set  up  by  any 
chemist  with  glassware  at  hand,  including  a  small  condenser,  the 
small  glass  tubing  to  be  bent  and  fitted  in 
stoppers,  as  shown  in  the  figure.  The  tube 
delivering  the  solvent  into  the  aqueous 
liquid  may  be  made  with  a  funnel- end,  as 
figured,  so  that  perforated  platinum  foil 
may  be  bound  over  the  expanded  orifice, 
.and  the  solvent  distributed  in  fine  streams. 
This  apparatus,  in  Fig.  5,  applies  the  hot 
vaporous  solvent  to  the  liquid  to  be  ex- 
tracted, which  is  therefore  maintained  at 
near  the  temperature  of  boiling  of  the  sol- 
vent. The  same  is  true  of  the  apparatus  of 
Neumann  and  of  Sell warz  (Figs.  4,  3).  For 
fats  this  heat  of  the  aqueous  mixture  is 
needful,  and  for  many  substances,  includ- 
ing some  alkaloids,  it  may  be  desirable,  but 
with  some  alkaloids  it  is  not  admissible. 
And  Eiloart  presents  a  modification  of  his 
apparatus  in  Fig.  6,  whereby  the  solvent 
reaches  the  aqueous  liquid  from  the  con- 
denser, and  not  directly  from  the  distilling 
flask ;  so  that,  if  the  condenser  be  kept  cold 
enough,  there  will  be  no  heating  of  the 
aqueous  liquid,  the  temperature  of  which  may  be  regulated  at 
will. 

All  the  forms  of  liquid-extraction  apparatus  so  far  described 
in  publications  are  devised  for  light  volatile  solvents,  constitut- 
ing the  layer  above  the  watery  liquid.  For  chloroform,  received 
in  the  layer  below  the  aqueous  one,  the  apparatus  illustrated  in 


lZeitsch,  anal.  Chem.,23,  368. 

2  1885  :  Ber.  d.  chem.  Ges.,  18,  3061. 


3  Chem.  News,  53,  281. 


40  ALKALOIDS. 

Fig.  Y  may  be  used,  with  attention  now  and  then, 
to  transfer  the  chloroformic  layer  to  the  distilling 
flask.  In  doing  this  the  valve  leading  to  the  con- 
denser is  closed,  the  lower  valve  is  opened,  and 
pressure  then  applied  at  the  outer  opening  of  the 
blow-tube  until  the  chloroformic  layer  is  siphoned 
over. 

The  degree  of  solubility  in  the  immiscible  sol- 
vents varies  with  forces  of  adhesion  and  cohesion 
not  operative  in  dissolving  from  the  dry  mass.  The 
solubility  of  an  alkaloid,  in  agitating  its  acidulous 
watery  solution  with  ether  or  benzene  at  the  mo- 
ment the  liquid  is  made  alkaline,  may  be  more  or 
less  abundant  than  the  solubility  of  the  dry  alka- 
loid in  ether  or  benzene.1  The  moment  of  liberation 
of  the  alkaloid  from  its  salt  is  certainly  the  most 
favorable  time  for  its  free  solubility.  Therefore 
many  operators,  in  dissolving  by  agitation,  add  first 
the  immiscible  solvent  and  agitate,  and  then  add 

the  alkali  for 
liberation  of 
the  alkaloid, 
when  the  agi- 
tation is  con- 
tinued. And 
it  is  to  be 
borne  in  mind 
that  the  fac- 
tors of  solubil- 
ity, reported 
for  a  certain 
solvent  with 
great  minute- 
ness precisely 
as  obtained  by 
experiment  at 
a  given  tem- 
perature, are- 
liable  to  vary  within  liberal  limits  by  influence  of  several  condi- 
tions besides  temperature. 

1  "Comparative  Determinations  of  the  Solubilities  of  Alkaloids  in  Crystal- 
line, Amorphous,  and  Nascent  Conditions  :  Water- washed  sol  vents  being  used." 
The  author,  1875  :  Pro.  Am.  Asso.  Adv.  Sci.,  24,  i.  Ill ;  Am.  Chem.,  6,  84; 
Jour.  Chem.  Soc.,  29,  403. 


FIGI7. 


ALKALOIDS.  41 

A  common  plan  for  separation  of  alkaloids  by  reason  of  their 
diverse  solubilities,  brought  into  use  at  a  very  early  period,  re- 
quires no  other  menstruum  than  water,  and  consists  in  dissolving 
out  the  alkaloid  as  a  salt,  by  use  of  acidulated  water,  and  preci- 
pitating the  alkaloid*  free,  by  adding  an  alkali  to  the  clear  aque- 
ous solution.  In  operations  of  this  sort  alkaloids  have  relations 
like  those  of  metallic  bases  other  than  the  alkalies.  Like  the 
metallic  bases,  alkaloids  are  in  some  instances  dissolved  by  free 
fixed  alkalies,  or  an  excess  of  this  alkali  precipitant,  in  other  in- 
stances dissolved  by  an  excess  of  ammonia,  and  in  many  cases 
not  dissolved  by  excess  of  any  alkali.  An  acidulous  watery  so- 
lution of  cinchona  bark,  in  the  clear  but  colored  filtrate,  on  add- 
ing solution  of  sodium  hydroxide  to  excess,  presents  an  abun- 
dant precipitate  of  the  mixed  impure  cinchona  alkaloids,  colored 
by  extracted  matters.  Precipitation  by  one  of  the  alkalies  or 
alkali  earths  has  a  place  in  various  processes  for  preparation  of 
alkaloids  from  vegetable  sources,  and  a  share  among  the  means 
of  qualitative  and  quantitative  analysis.  Thus  in  most  of  the 
methods  of  the  morphiometric  assay  of  opium,  ammonia  is  added 
to  the  aqueous  solution  of  morphine  salt,  when  simple  trans- 
position occurs,  as  follows :  (C17H19]SrO3)2H2SO4+2]m4OH:= 
2C17H19:N"O3  H2O(cryst.  morp£ine)+(NH^O4,  In  one  of 
the  preferred  methods  the  morphine  is  dissolved  out  of  the 
opium  by  an  excess  of  lime,  the  resulting  lime-solution  being 
treated  with  ammonium  chloride,  when  a  transposition  occurs, 
precisely  corresponding  to  that  of  a  precipitate  of  aluminium  hy- 
droxide according  to  the  equation  :  K2Al2O4+2NH4Cl-f-4:H2O= 
A12(OH)6+2KC1+2]NTI4OIL  And  no  more  absolute  separa- 
tion of  the  chief  alkaloid  of  opium  than  this  crystalline  preci- 
pitation (favored  by  the  contact  of  immiscible  solvents)  has  yet 
been  established. 

The  action  of  certain  of  the  alkalies,  used  in  excess,  to  re- 
dissolve  the  precipitates  they  form  in  solutions  of  alkaloid  salts, 
has  been  made  available  in  analytical  separations. 

Fresenius's  manual  of  qualitative  analysis  has  long  presented 
a  scheme  of  separation,  or  of  classification,  of  a  few  common 
alkaloids,  as  follows :  Of  Non- volatile  Alkaloids,  (1)  those 
which  are  precipitated  by  potassa  or  soda  from  the  solutions  of 
their  salts,  and  redissolve  readily  in  an  excess  of  the  precipitant 
(morphine)  ;  (2)  those  which  are  precipitated  by  potassa  or  soda 
from  the  solutions  of  their  salts,  but  do  not  redissolve  to  a  per- 
ceptible extent  in  an  excess  of  the  precipitant,  and  are  precipi- 
tated by  sodium  bicarbonate  even  from  acid  solutions  (narcotine, 
quinine,  cinchomne) ;  (3)  those  which  are  precipitated  by  potassa 


42  ALKALOIDS. 

from  the  solutions  of  their  salts,  and  do  not  redissolve  to  a  per- 
ceptible extent  in  an  excess  of  the  precipitant,  but  are  not  pre- 
cipitated from  (even  somewhat  concentrated)  acid  solutions  by 
the  bicarbonates  of  the  fixed  alkali  metals  (strychnine,  brucine, 
veratrine,  atropine).  The  solubility  of  quinine,  and  the  far  more 
difficult  solution  of  the  other  cinchona  alkaloids,  in  an  excess  of 
ammonia,  is  used  in  the  valuable  method  of  Kerner  for  separa- 
tion of  quinine  from  other  cinchona  alkaloids,  and  estimating 
the  proportions  or  fixing  the  limits  of  the  latter. 

Finally,  it  remains  to  notice  that,  although  the  salts  of  the 
common  mineral  acids  (sulphuric,  hydrochloric,  nitric)  with  the 
alkaloids,  are  soluble  in  water,  there  are  certain  double  salts 
whereby  nearly  all  alkaloids  are  precipitated,  in  somewhat  com- 
plex compounds  nearly  insoluble  in  water.  The  precipitants  are 
known  as  The  General  Reagents  for  Alkaloids.  The  most  use- 
ful of  these  are  (1)  Iodine  in  solution  of  potassium  Iodide,  (2) 
Potassium  Mercuric  Iodide,  (3)  Phosphomolybdate,  (4)  Bromine 
in  aqueous  hydrobromic  acid,  (5)  Potassium  Cadmium  Iodide, 
(6)  Potassium  Bismuth  Iodide,  (7)  Tungsten  compounds,  phos- 
phoantimonic  acid,  and  ferric  chloride  with  hydrochloric  acid, 
(8)  Tannic  Acid,  (9)  Picric  Acid. 

In  applying  a  precipitant  to  a  solution  of  an  alkaloid,  when 
it  is  desired  to  avoid  expenditure  of  the  material  under  examina- 
tion, a  drop  of  the  solution  is  to  be  treated  with  a  drop  of  the 
reagent,  on  a  glass  slide  placed  over  black  paper.  A  hand- 
magnifier  is  serviceable. 

(1)  Iodine  in  Potassium  Iodide  Solution  ( WAGNER,  1866).1 — 
A  decinormal  solution  of  the  free  iodine  :  12.66  grams  of  iodine 
in  a  liter  of  solution  of  iodide  of  potassium  ;  or,  20  grams 
iodine  and  50  grams  potassium  iodide  per  liter  (WOKMLEY). 
Applied,  as  it  is,  in  acidified  solution,  it  is  in  effect  iodized 
hydriodic  acid.  Brown  and  flocculent  precipitates ;  generally 
with  very  little  solubility  in  water ;  formed  more  perfectly  in 
acidulous  solutions,  and  iii  those  containing  a  little  free  sul- 
phuric acid.  Iodine  tincture  is  a  less  useful  form  of  the  re- 
agent. The  precipitates  are  more  or  less  soluble  in  alcohol. 
A  very  slight  addition  of  the  reagent  is  sufficient,  and  it  is 
better  not  to  use  enough  to  give  color  to  the  solution.  In  a 
liquid  liable  to  contain  dissolved  substances  not  alkaloids,  the 
fact  of  precipitation  is  not  strongly  characteristic,  while  the 
absence  of  precipitation  is  conclusive  for  ordinary  alkaloids. 

1  Zeitsch.  anal.  Chem.,  4,  387. 


GENERAL  REAGENTS.  43 

On  standing,  the  precipitates  in  most  instances  crystallize  in 
somewhat  characteristic  forms,  more  perfectly  from  solutions  in 
alcohol. 

In  composition  (HiLGEK,  1869  ;  BAUER,  1874)  the  precipitates 
are  addition  compounds,  of  different  but  related  types.  When 
quinine  sulphate  solution  is  treated  with  a  little  of  the  reagent, 
there  is  formation  of  C20H24]^2O2.HI.I  ;  with  more  of  the  re- 
agent, quinine  pentiodide,  C20H24Sr2O2 .  HI .  I4,  is  formed ;  and  in 
presence  of  excess  of  alcoholic  iodine  and  sulphuric  acid, 
various  iodosulphates  are  formed,  as  stated  more  fully  un- 
der Quinine,  d,  "  Herapathite  test."  Atropine  pentiodide, 
C17H23NO3 .  HI5,  obtained  by  excess  of  the  reagent,  crystallizes 
from  hot  alcoholic  solution,  in  fine  blue-green,  lustrous  needles 
or  plates.  A  corresponding  tri-iodide  is  obtained  by  adding  less 
of  the  iodine.  Strychnine  tri-iodide  crystallizes  from  alcoholic 
solution  in  long,  dark-brown  prisms,  of  rhombic  shapes,  with 
bluish-metallic  lustre.  Thrown  down  as  an  amorphous  preci- 
pitate it  is  red-brown.  Berberine  tri-iodide,  C20H1?]N"O4.HI3, 
crystallizes  from  hot  alcohol  in  long,  red-brown,  diamond-lus- 
trous needles.  Piperine  tri-iodide,  (C17H19]SrO3)2HI3  (JoKGEN- 
JSEN,  1877),  crystallizes  from  hot  alcoholic  solution  in  long,  steel- 
blue  needles  of  metallic  lustre. 

Recovery  of  the  free  alkaloid  from  the  precipitates  of  hy- 
periodides  may  be  accomplished  as  follows  :  The  washed  preci- 
pitate is  dissolved  in  excess  of  aqueous  sulphurous  acid,  and  the 
solution  evaporated  on  the  water-bath,  the  sulphurous  acid  being 
kept  in  excess  until  the  hydriodic  acid  is  expelled,  when  the 
former  is  also  driven  off  and  the  alkaloid  remains  as  a  sulphate. — 
The  hyperiodide  precipitates  dissolve  in  solution  of  thiosulphate, 
and  may  be  thereby  separated  from  various  foreign  matters 
carried  down  by  adding  free  iodine  to  organic  extracts.  If  the 
thiosulphate  solution  be  treated  with  the  iodine  solution  in  ex- 
cess, the  alkaloid  is  again  precipitated. 

(2)  Potassium  Mercuric  Iodide.     Mayer's  Solution* — The 

JF.  L.  WINCKLER,  1830.     A.  v.  PLANTA-REICHENATJ,  "Das  Verhalten  der 
wichtigsten  Alkaloidegegen  Reagentien  "  (S.  41),  Heidelberg,  1846.     THOMAS  B. 
GROVES,  "  On   some  compounds  of  iodide  and  bromide  of  mercury  with  the 
alkaloids,"  1859:  Jour.  Chem.  Soc.,  n,  97,  188  ;   Phar.  Jour.  Trans.,  18,  181 
Am.  Jour.  P^>/r.,  36,  535.     FERDINAND  F.  MAYER,  1862-3:  Pro.  Am.  Pharm. 
1862,  238;  and    Chem.  News,  7,  159;  8,   177,  189  ;  Am.   Jour.  Phar.,  35,  20 
Zeitsch.  anal.  Chem,  2,    225;    Jahr.   Chem.,  1863,  703.     G.  DRAGENDORFF. 
"Werthbestimmung,"  1874,  p.  9  and  elsewhere.     A.  B.    PEESCOTT,  "Estima- 
tion of  alkaloids  by  potassium  mercuric   iodide,"  J880:  Am.  Chem.  Jour.,  2, 
294;  Jour.  Chem.  Soc.,  42,  664:  Chem.   News,  45,  \U;Ber.  d.  Chem.  Oea., 
14,  1421. 


44  ALKALOIDS. 

solution  proposed  by  Mayer  is  the  one  generally  used  for  pur- 
poses qualitative  or  quantitative.  It  is  a  deciiiormal  solution  of 
£(HgCl3+6KI)  =  the  hydrogen  equivalent  of  Hg.  Of  dry, 
crystallized  mercuric  chloride,  13.525  grams ;  potassium  iodide, 
49.680  grams ;  separately  dissolved  in  water,  and  the  mixed  solu- 
tions made  up  to  one  liter.  The  reactions  of  the  solution  appear 
to  correspond  with  the  formula  KIHgI2.(KI)3+2KCl,1  instead 
of  (KI)2HgI2+2KI+2KCl.  Dragendorff  prefers  to  make  quan- 
tities, above  specified,  to  2  liters  instead  of  1. 

Mayer's  solution  is  applied  only  in  acidulous  solutions,  in 
testing  for  alkaloids ;  therefore  ammonia  does  not  interfere,  as 
the  precipitate  of  mercurammonium  iodide  is  not  formed  in  pre- 
sence of  free  acids.  The  acidulation  may  be  with  sulphuric  or 
hydrochloric  acid,  and  may  be  strong  without  dissolving  the 
precipitate.  The  solution "  tested  must  not  be  alcoholic,  and 
must  not  contain  acetic  acid.  Some  organic  matters  other  than 
alkaloids  cause  precipitates.  With  strychnine  the  precipitate  is 
obtained  in  dilution  of  1  to  150000  ;  with  quinine,  in  solutions 
of  about  the  same  dilution ;  while  with  morphine,  or  with  atro- 
pine,  solutions  of  1  to  4000  do  not  give  the  precipitate.  The 
precipitates  are  curdy  or  flocculent,  and  for  the  most  part  of  a 
yellowish-white  color. 

Caffeine  and  theobromine  are  not  precipitated  by  potassium 
mercuric  iodide. 

The  composition  of  some  of  the  alkaloid  iodomercurates 
varies  with  conditions  of  concentration,  excess  of  reagent,  and 
acidity ;  while  the  precipitates  of  other  alkaloids  are  nearly  con- 
stant in  composition.  With  strychnine  the  precipitate  is  not  far 
from  C21H22N2O2HIHgI2a ;  with  morphine  the  precipitate  cor- 
responds to  a  variable  mixture  of  (C17HpNO3)4(HI)4(HgI2)3  and 
(C17H19NO3)4(HI)6(HgI2)3  ;  with  quinine  the  precipitation  ap- 
pears to  be  most  nearly,  though  not  closely,  represented  by 
(C20H24N2O2)2(HI)3(Hgl2)3  ;  and  with  atropine  the  gravimetric 
value  of  the  precipitate  does  not  correspond  to  its  volumetric 
factor. 

In  volumetric  use  the  "  end-reaction  "  is  denoted  only  by  the 

'In  the  proportions  for  (KI)2HgI2+2KCl,  the  mercuric  iodide  remains  dis- 
solved only  in  concentrated  or  hot  solution.  The  quantity  of  alkali  iodide 
adopted  by  Mayer  cannot  be  very  much  reduced  and  retain  solubility  at  the 
decinormal  dilution  in  the  cold.  A  permanent  solution  with  the  help  of  bro- 
mide can  be  obtained  as  follows:  HgCl2  +  4KI  +  KBr  :  mercuric  chloride, 
13.525  ;  potassium  iodide,  33.12  ;  potassium  bromide,  5.94;  water  to  1000  by 
volume.  This  solution  may  be  supposed  to  contain  (KI)2HgI2  +  KBr  +  2KCL 
(The  author,  1880:  Am.  Ghem.  Jour.,  2,  304.) 

2  The  author,  1880  :  Am.  Chem.  Jour.,  2,  296. 


GENERAL  REAGENTS.  45 

completed  precipitation. '  After  the  last  addition  from  the  bu- 
rette the  precipitate  is  either  allowed  to  subside,  or  a  little  por- 
tion is  filtered  out  and  a  drop  of  the  reagent  added  from  the  bu- 
rette to  the  clear  solution.  Some  of  the  precipitates  subside 
readily,  strong  acidulation  usually  favoring  this  result ;  with 
others  much  time  is  required,  and  titration  in  this  way  is  gene- 
rally slow.  Filtration  is  the  better  way  :  using  a  minute  niter, 
not  over  5  millimeters  or  J  inch  in  radius,  held  in  a  loop  of  pla- 
tinum wire  or  a  coil  of  drawn-out  glass  tubing,  over  a  glass  slide 
placed  upon  black  paper.  A  drop  or  two  is  taken,  with  the  stir- 
ring-rod, from  the  mixture  containing  the  precipitate,  filtered 
through  the  wet  filter,  and  treated  over  the  black  ground  with  a 
drop  of  the  reagent  from  the  burette,  when  the  slightest  turbid- 
ity can  be  seen.  Before  the  end  of  the  titration  all  the  test-por- 
tions are  drained  and  rinsed  with  a  few  drops  of  water  passed 
through  the  filter  into  the  mixture  containing  the  precipitate. 

In  volumetric  estimation  the  strength  of  the  alkaloidal  solu- 
tion should  usually  be  1  of  alkaloid  to  200  of  solution — a  second 
estimation  being  made,  if  need  be,  for  this  graduation.  The 
quantity  of  alkaloid  precipitated  by  1  c.c.,  under  given  condi- 
tions of  concentration,  etc.,  is  stated  with  the  directions  for  quan- 
titative work  on  the  several  alkaloids  described  in  this  work.  A 
quite  full  list  of  the  volumetric  factors  for  Mayer's  solution  was 
given  by  Mayer,  and  some  of  these  have  been  subjected  to  con- 
trol analyses  by  Dragendorff  and  others ;  but  the  presentation  of 
such  a  list  is  here  intentionally  avoided.  It  must  be  understood 
that  the  alkaloidal  equivalent  of  one  c.c.  varies  with  the  condi- 
tions, especially  with  that  of  concentration.  Unless  the  analyst 
has  good  authority  for  an  alkaloid  equivalent,  given  with  speci- 
fied conditions,  he  should  standardize  his  Mayer's  solution,  with 
an  alkaloid  solution  of  known  strength,  for  himself,  holding  de- 
grees of  concentration,  acidulation,  mass,  and  time  the  same  for 
the  titration  of  the  solution  of  unknown  strength  that  they  are 
for  the  solution  of  known  strength  of  alkaloid.  The  end  of  the 
reaction  is  the  point  when  further  addition  of  the  reagent  ceases 
to  cause  a  precipitate.  Before  this  point  is  reached,  however,  in 
some  cases  the  addition  of  a  drop  of  the  solution  of  the  alkaloid 
will  cause  a  precipitate — the  mixture  having  attained  a  composi- 
tion of  equilibrium  (not  very  rare  among  chemical  reactions)  in 
which  precipitation  is  caused  by  a  drop  of  either  the  iodomercu- 
rate  or  the  alkaloid  solution.  When  the  precautions  here  re- 

1  Trials  of  various  indicators  for  the  end-reaction  were  reported  by  the 
author  in  Am.  Chem.  Jour. ,  2,  304,  where  also  attention  is  called  to  the  error 
of  Mayer's  direction  to  titrate  back  with  silver  nitrate. 


46  ALKALOIDS. 

quired  are  observed,  titration  with  Mayer's  solution  becomes  a 
trustworthy  means  of  estimation. 

The  alkaloids  can  be  obtained  from  their  iodomercurate  pre- 
cipitates by  triturating  the  washed  precipitate  with  stannous 
chloride  solution  and  potassium  hydroxide  to  strong  alkaline 
reaction,  and  then  exhausting  with  ether  or  chloroform  or  ben- 
zene as  a  solvent  for  the  alkaloids.  Strong  alcohol  can  be  used 
as  a  solvent  if  potassium  carbonate  be  taken  instead  of  potassium 
hydroxide. — Also,  the  mercury  can  be  removed  from  the  precipi- 
tates by  dissolving  in  alcohol,  adding  acid  if  need  be,  treating 
with  hydrogen  sulphide  gas,  and  filtering.  The  filtrate  can  be 
freed  from  iodine,  if  this  be  desired,  after  expelling  the  hydrogen 
sulphide,  by  adding  some  excess  of  silver  nitrate  solution,  filter- 
ing, adding  hydrochloric  acid  to  the  filtrate,  and  filtering  again. 

(3)  Phosphomolybdate  * — A  fixed  alkali  phosphomolybdate 
in  strong  nitric  acid  solution — in  effect  a  solution  of  phosphomo- 
lybdic  acid. 

Applicable  in  acidulous  solutions  and  in  absence  of  ammo- 
nium salts  and  free  ammonia,  which  also  precipitate  it. 

It  is  prepared  as  follows  :  The  yellow  precipitate  formed  on 
mixing  acid  solutions  of  ammonium  molybdate  and  sodium  com- 
mon phosphate — the  ammonium  phosphomolybdate — is  well 
washed,  suspended  in  water,  and  heated  with  sodium  carbonate 
until  completely  dissolved.  The  solution  is  evaporated  to  dry- 
ness,  and  the  residue  gently  ignited  till  all  ammonia  is  expelled, 
sodium  being  substituted  for  ammonium.  If  blackening  occurs, 
from  reduction  of  molybdenum,  the  residue  is  moistened  with 
nitric  acid  and  heated  again.  It  is  then  dissolved  with  water 
and  nitric  acid  to  strong  acidulation ;  the  solution  being  made 
ten  parts  to  one  of  the  residue.  It  must  be  kept  from  contact 
with  vapor  of  ammonia,  both  during  preparation  and  while  pre- 
served for  use. 

The  precipitates  of  alkaloids,  by  adding  this  reagent  to  their 
acidified  solutions,  are  amorphous,  and  of  yellowish  colors,  some- 
times orange-yellow,  in  other  cases  brown-yellow.  In  general 
they  have  very  little  solubility,  and  are  obtained  in  very  dilute 
solutions.  Besides  ammonia,  other  bodies  not  alkaloids  are  liable 
to  give  precipitates  with  this  reagent.  A  negative  result  is  trust- 
worthy for  the  exclusion  of  more  than  traces  of  alkaloids  in  the 
solution  tested.  Most  of  the  precipitates  are  soluble  in  ammonia, 
and  those  of  alkaloids  that  are  strong  reducing  agents  mostly  dis- 

1  SONNENSCHEIN,  1857:  Ann.  Chem.  Phar.,  104,  45.  DE  VRIJ:  Jour,  de 
Pharm.,  26,  219.  STRUVE,  1873:  Zeitsch.  anal.  Chem.,  12,  170. 


GENERAL  REAGENTS.  47 

solve  with  the  blue  color  of  reduced  molybdic  acid,  or  with  some 
shade  caused  by  admixture  of  blue.  The  ammoniacal  solution 
is  blue  with  aconitine,  aniline,  atropine,  berberine,  morphine, 
nicotine,  and  physostigmine.  Alcohol  and  ether  do  not  dissolve 
the  precipitates,  and  acetic  acid  has  but  a  slight  solvent  action. 

The  alkaloids  can  be  recovered  from  the  precipitates  by  add- 
ing potassium  or  sodium  hydroxide  solution,  and  shaking  out 
with  an  immiscible  solvent  for  the  alkaloid,  as  ether,  chloroform, 
benzene,  or  amyl  alcohol.  Adding  potassium  carbonate  instead 
of  hydroxide,  strong  alcohol  can  be  added  instead  of  an  immis- 
cible solvent. 

A  gravimetric  value  of  the  phosphomolybdate  precipitate  has 
been  obtained  for  a  few  of  the  alkaloids,  but  it  has  not  been 
ascertained  what  conditions  are  necessary  to  secure  a  constant 
composition.1 

(4)  Bromine  in  aqueous  hydrobromic  acid. — WOEMLEY  di- 
rects the  use  of  aqueous  hydrobromic  acid  saturated  with  bromine. 
Applicable   to   aqueous  solutions  of   the  salts  of  the  alkaloids, 
neutral  or  slightly  acidulous  witli  a  mineral  acid,  and  in  absence 
of  acetic  acid  and  of  alcohol,  which  dissolve  the  precipitates. 
Besides  alkaloids,  the  phenols  and  other  bodies  give  precipitates 
with  bromine.     (See  Phenol.)     The  limit  of  precipitation  of  the 
alkaloids  is  at  dilution  to  from  5000  to  100000  parts — with  mor- 
phine, 1  to  2500 ;  with  nicotine  or  conine,  1  to  10000  ;  with  aco- 
nitiiie,  codeine,  or  brucine,  1  to  25000 ;  with  strychnine,  narco- 
tine,  or  veratrine,  1  to  100000  (WOEMLEY).     In  general  the  pre- 
cipitates are  amorphous  ;  with  atropine,  crystalline. 

(5)  Potassium  cadmium  iodide  (MAEME,  1866). — Prepared 
by  saturating  a  boiling  concentrated  solution  of  potassium  iodide 
with  cadmium  iodide,  and  adding  an  equal  volume  of  cold-satu- 
rated solution  of  potassium  iodide.     In  diluted  solution,  precipi- 
tation is  apt  to  occur. — This  reagent  precipitates  the  aqueous  so- 
lutions of  alkaloid  salts,  acidified  by  sulphuric  acid,  the  precipi- 
tates being  soluble  in  excess  of  the  precipitant,  or  in  alcohol. 
Amorphous  at  first,  the  precipitates  become  crystalline. — The  al- 
kaloids can  be  recovered  from  the  precipitates  as  directed  for 
those  formed  by  potassium  mercuric  iodide. 

(6)  Potassium  bismuth  iodide  (DEAGENDOEFF,  1866). — Pre- 
pared from  bismuth  iodide,  in  the  way  directed  for  the  last- 

1  It  appears  probable  that  a  dilute  solution  of  the  phosphomolybdatp. 
standardized  by  solution  of  an  alkaloid  of  known  strength,  could  be  used  1o 
estimate  the  quantity  of  the  same  alkaloid  under  strictly  parallel  conditions. 
The  end-reaction  can  be  found  as  directed  for  Maver's  solution. 


48  ALKALOIDS. 

named  reagent.  Cannot  be  diluted.  Applicable  as  a  precipitant 
to  aqueous  solutions  of  alkaloid  salts,  strongly  acidified  with 
sulphuric  acid. 

(7)  Metatungstic    acid,   Phosphotungstic  acid  (SCHEIBLER, 
I860),  Silicotungstic  acid  (GODEFFROY,  1876),  and  Phospho-anti- 
wwmc  acid  (SCHULTZE,  1859),  have  been  used  as  general  preci- 
pitaiits  for  the  alkaloids.     GODEFFROY  (1877)  uses  a  solution  of 
ferric  chloride  in  hydrochloric  acid  as  a  precipitant  for  alkaloids. 

(8)  Tannic  acid  (BERZELIUS,  HENRY,  DUBLANC,  HAGER),  in 
solution  with  8  parts  of  water  and  1  part  of  alcohol,  gives  whitish, 
grayish-white,  or  yellowish  precipitates  with  nearly  all  the  alka- 
loids.    In  the  larger  number  of  instances  these  precipitates  are 
easily  soluble  in  acids,  frequently  dissolving  in  excess  of  the  tannic 
acid  ;  on  the  contrary,  some  of  the  alkaloids  are  precipitated  by 
tannic  acid  only  in  strong  acid  solutions.     Ammonia  dissolves 
the  tannates  of  the  alkaloids. 

Dilute  acetic  acid  dissolves  the  precipitates  of  tannates  of 
aconitine,  brucine,  caffeine,  colchicine,  morphine,  physostigmine, 
and  veratrine  ;  acetic  acid  not  dilute,  the  precipitate  of  quinine. — 
Cold  dilute  hydrochloric  acid  does  not  dissolve  the  precipitates 
of  tannates  of  aconitine,  berberine,  brucine  (dissolves  sparingly), 
caffeine,  cinchonine,  colchicine  (dissolves  slightly),  narcotine, 
papaverine,  thebaine,  solanine,  strychnine  (dissolves  slightly), 
veratrine. — Cold  dilute  sulphuric  acid  does  not  dissolve  the  pre- 
cipitates of  tannates  of  aconitine,  physostigmine,  quinine,  sola- 
nine,  veratrine. — Precipitates  are  completely  formed  in  solutions 
strongly  acidulated  with  sulphuric  acid,  by  aconitine,  physostig- 
mine, and  veratrine,  though  none  of  these  alkaloids  gives  a 
full  precipitate  in  slightly  acidulated  solution. — Alkaloids  are 
recovered  from  their  tannates  by  mixing  the  moist  precipitate 
with  lead  oxide  or  carbonate,  drying  the  mixture,  and  extracting 
with  an  immiscible  solvent  or  with  alcohol. 

(9)  Picric  acid,  HC6H2(]SrO2)3O   (WORMLEY,  1869 ;  HAGER, 
1869). — Used  in  very  dilute,  saturated  aqueous  solution,  or  in  a 
sparing  addition  of  the  alcoholic  solution.     Applied  as  a  preci- 
pitant of  alkaloids  in  their  neutral  solutions,  or,  better,  in  solu- 
tions acidulated  with  sulphuric  acid.     Many  of  the  precipitates 
become  crystalline,  and  give  characteristic  forms  under  the  mi- 
croscope ;  in  general  they  have  a  yellow  or  yellowish- white  color. 
"With  morphine  the  precipitate  is  formed,  in  drop-tests,  in  solu- 
tion of  1  to  500 ;  with  aconitine,  atropine,  or  veratrine,  in  solu- 
tion of  1   to  5000 ;  with  brucine  or  narcotine,  in  a  solution  of 


GENERAL  REAGENTS.  49 

1  to  20000 ;  with  strychnine,  1  to  25000  ;  with  nicotine,  in 
solution  of  1  to  4000  (WORMLEY). — The  alkaloids  can  be  re- 
covered from  their  picrate  precipitates  by  adding  an  alkali  solu- 
tion and  exhausting  with  a  solvent  immiscible  with  water,  or  by 
evaporating  to  dry  ness  with  a  solution  of  potassium  or  sodium 
carbonate,  and  extracting  with  alcohol. — HAGER  has  used  preci- 
pitation with  picrate  in  some  estimations  of  alkaloids.  For 
cinchona  alkaloids,1  10  grams  of  the  powdered  bark,  covered 
with  130  c.c.  water,  with  20  drops  of  caustic  potassa  solution 
of  s.g.  1.3,  are  digested  at  boiling  temperature  and  stirred  for  a 
quarter  of  an  hour.  Of  dilute  sulphuric  acid,  s.g.  1.115,  15 
grams  are  added,  and  the  mixture  boiled  15  to  20  minutes. 
"When  cold  the  whole  is  made  up,  by  the  addition  of  water,  to 
110  c.c.  ("  the  volume  of  110  grams  of  water ").  The  mixture 
is  filtered,  through  a  paper  filter  of  10.5  to  11.0  centimeters 
(8J  inches)  diameter,  into  a  graduated  jar,  and  the  volume  of  the 
filtrate  (about  60  c.c.)  noted.  To  this  filtrate  (100  c.c.  of  which 
represents  the  10  grams  of  bark)  picric  acid  solution  saturated 
in  the  cold  is  added,  in  quantity  about  50  c.c.,  or  enough  to 
complete  the  precipitation  (as  ascertained  by  allowing  a  few 
drops  to  flow  down  the  side  of  the  vessel).  After  half  an  hour 
the  precipitate  is  gathered  on  a  weighed  filter,  washed,  and  dried 
between  blotting-papers  over  the  water-bath.  The  dried  preci- 
pitate of  picrates  of  cinchona  alkaloids  contains  (according  to 
Hager)  two  molecules  of  picric  acid  as  anhydride,  440  parts,  to 
one  molecule  of  cinchona  alkaloid,  308  to  324  parts,  without 
water  of  crystallization.  Or  8.24  parts  of  the  precipitate  indi- 
cate about  3.5  of  mixed  cinchona  alkaloids.  Then  the  noted 
number  of  c.c.  of  decoction  taken :  100 : :  the  indicated  quan- 
tity of  mixed  alkaloids  in  the  precipitate  :  x  =  quantity  mixed 
alkaloids  in  the  10  grams  of  bark. 

(10)  Platinic  Chloride.  Auric  Chloride.— Solutions  of  these 
salts,  hardly  to  be  classed  as  special  reagents  for  alkaloids,  yet 
give  precipitates  with  the  greater  number  of  them.  Platinic 
chloride  is  often  required  in  establishing  distinctions  between 
alkaloids,  as  noted  in  this  work  under  the  qualitative  reactions 
of  the  respective  compounds.  The  same  may  be  said  of  auric 
chloride.  The  melting  points  of  the  alkaloidal  compounds  of 
these  metals  serve  as  constants  useful  for  identification,  especially 
in  distinguishing  the  derivatives  of  alkaloidal  radicals.  The 
composition  of  these  metallic  precipitates  has  in  most  cases  been 

'1869  :  Phar.  Centralh.,  p.  145  ;  Zeitsch.  anal.  Chem.,  8,  477. 


50  ALKALOIDS. 

estimated  from  the  percentages,  respectively,  of  metallic  platinum 
and  metallic  gold,  left  after  ignition.  These  percentages  were 
much  depended  upon  in  the  earlier  years  of  the  chemistry  of  the 
alkaloids,  and  are  given  full  and  prominent  statements  in  Gme- 
lin's  Hand-book  of  Chemistry. — The  platinum  precipitates  are 
divisible  into  those  which  do  and  those  which  do  not  dissolve 
in  hydrochloric  acid — cinchonine  and  quinine,  morphine,  and 
strychnine  being  placed  among  those  not  readily  soluble  in  this 
acid. — The  platinum  precipitates  have  a  yellow  or  yellowish 
color.  The  gold  precipitates  of  a  number  of  the  alkaloids 
blacken  by  reduction  on  standing. 

Color-reactions  of  the  Alkaloids. — In  general  it  should  be 
borne  in  mind  that  color-reactions  are  subject  to  variation  (1)  by 
impurities  of  the  alkaloidal  material,  (2)  by  impurities  of  the 
reagent,  and  (3)  by  conditions  of  concentration,  mass  preponde- 
rance, temperature,  and  time.  Also,  that  the  best  authority  to 
guide  the  operator  is  the  result  of  a  control-test  upon  a  known 
portion  of  the  alkaloid  in  question,  holding  all  conditions  to  be 
the  same. 

Concentrated  Sulphuric  Acid  1  dropped  upon  the  dry  alka- 
loid, on  a  white  porcelain  surface  or  on  glass  over  a  white 
ground,  without  heating,  reacts  as  follows  :  colorless  with  atro- 
pine,  caffeine,  chelidoiiine,  cinchonidine,  cinchonine,  codeine, 
hyoscine,  hyoscyamine,  morphine,  nicotine,  pilocarpine,  quini- 
dine,  quinine,  staphisagrine,  strychnine,  theobromine.  Of  these, 
on  warming,  a  purplish  to  browrn  color  is  given  by  morphine. 
Yellowish  colors  are  given  by  colchicine,  gnoscopine,  and  jer- 
vine ;  reddish  colors  are  given  (either  at  once  or  after  a  short 
time)  by  apornorphine,  brticine  (pale  rose),  conine  (pale),  gelse- 
minine,  mecoiiidine,  narceine  (to  black),  narcotine  (yellow-red  to 
violet  and  blue),  nepaline,  physostigmine,  rhoeadine,  sabadilline, 
sabatrine,  solanine,  taxine,  thebaine,  veratrine,  and  veratroidine ; 
bluish  colors  are  given  by  cryptopine,  curarine  (on  standing),  and 
papaverine ;  and  greenish  colors  by  beberine,  berberine,  emetine 
(brown  to  green),  piperine,  pseudomorphine,  and  rhoeadine. — Of 
glucosides,  reddish  colors  (mostly  bright)  are  given  by  amygda- 
lin,  %colombin,  cubebin,  elaterin,  hesperidin,  phloridzin,  populin, 
salicin,  sarsaparillin,  senagin,  smilacin,  syringin,  tannic  acids. 

1  Traces  of  nitric  acid,  not  infrequent  as  an  impurity  in  "  C.  P.  sulphuric 
acid,"  cause  a  great  difference  in  the  reaction  with  morphine  and  other  alka- 
loids colored  by  nitric  acid.  See  the  composition  of  "  Erdmann's  reagent," 
given  in  the  foot-note  under  Nitric  Acid  Color  Tests.  On  the  Reactions  of 
Alkaloids  with  Sulphuric  Acid,  cold,  warm,  and  hot— alone,  with  nitric  acid, 
and  with  permanganate — see  GUY,  1861-2:  Phar.  Jour.  Trans,  [2],  2,  558,  662  ; 
3,  11,  112  ;  Zeitsch.  anal.  Chem.,  i,  90. 


GENERAL   REAGENTS.  51 

Froehdds  Reagent — concentrated  sulphuric  acid  containing 
molybdio  acid.1 — A  solution  of  0.001  gram  of  molybdic  acid  or 
alkali  molybdate,  in  1  c.c.  of  concentrated  sulphuric  acid  (DRA- 
GENDORFF),  freshly  prepared  by  the  aid  of  heat,  and  used  when 
cold.  FKOEHDE  took  0.005  gram  of  the  molybdate  to  1  c.c.  of 
sulphuric  acid,  and  BUCKINGHAM  took  as  much  as  1  part  of 
molybdate  to  15  of  the  sulphuric  acid  ;  but  the  more  attenuated 
proportion  of  the  molybdate  (1  to  1840)  gives  the  more  dis 
tinctive  reactions. — The  reduction  of  molybdic  acid  to  hydrated 
molybdic  molybdate  is  attended  with  a  bright  blue  color.  This 
reduction  occurs  in  concentrated  sulphuric  acid,  by  heat  alone, 
at  the  temperature  of  incipient  vaporization  of  the  sulphuric 
acid.  Numerous  inorganic  and  organic  reducing  agents  cause 
the  reduction  and  give  the  color  to  molybdate.  As  a  character- 
izing reaction  it  is  applied  mostly  to  alkaloids,  when  iion-alka- 
loidal  matter  must  be  excluded,  and  the  more  dilute  solution  of 
molybdate  is  the  more  trustworthy. 

Froehde's  reagent  gives  no  color  with  atropine,  caffeine,  cin- 
chonidine,  cinchonine,  conine,  delphinine,  hyoscine,  hyoscya- 
mine,  nicotine,  strychnine,  theobromine  ;  yellowish  colors  with 
aconitine,  colchicine,  piperine  ;  reddish  colors  with  brucine,  eme- 
tine (red  changing  to  green),  narceine  (changing  to  blue),  saba- 
dilline  (reddish-violet),  solanine,  thebaine  (orange),  veratrine  (gra- 
dually, cherry-red) ;  bluish  colors  with  codeine  (gradually,  deep 
blue),  morphine  (violet  to  blue),  narceine  (yellowT-brown  to  red 
and  blue),  staphysagrine  (violet-brown) ;  greenish  colors  with 
apomorphine  (green  to  violet),  beberine  (brown-green),  berberine 
(brown-green),  emetine  (red  changing  to  green  and  turned  blue 
by  hydrochloric  acid),  quinine  (pale),  quinidine  (pale). —  Of  glu- 
cosides,  colocynthin  gives  slowly  a  cherry-red  color ;  elaterin, 
yellow  ;  phloridzin,  slowly,  blue  ;  populin,  violet ;  salicin,  violet 
to  cherry-red  ;  syringin,  blood-red  to  violet-red  colors. 

Nitric  acid,  of  s.g.  1.40  to  1.42,  applied  in  a  drop  to  the  dry 
alkaloid  upon  white  porcelain,  gives  a  color,  frequently  reddish, 
with  numerous  alkaloids.  No  color  is  obtained  with  atropine,  caf- 
feine, cinchonidine,  cinchonine,  conine,  gelseminine,  quinidine, 
quinine,  strychnine,  theobromine.  Yellowish  colors  are  obtained 

1  FROEHDE,  1866:  Archiv  der  Phar.,  126,  54;  Zeitsch.  anal.  Chem.,  5,  214; 
Pro.  Am.  Pharm.,  15,  241.  ALMEN,  1868:  N.  Jahr.  /.  Phar.,  30,  87;  Zeitsch. 
anal.  Chem.,  8,  77.  KAUZMANN,  1869:  Zeitsch.  anal.  Chem.,  8,  105.  BUCK- 
INGHAM, 1873:  Jour.  Chem.  Soc.,  27,  715;  Am.  Jour.  Phar.,  45, 179.  DRAGEN- 
DOR.FF,  1872:  "  Beil  rage  zur  gericht.  Chem.  organ.  Gifte."  A.  B.  Prescott, 
1876:  "  Froehde's  Reagent  as  a  Test  for  Morphine,"  Am.  Jour.  Phar.,  48,  59; 
Jahr.  der  Pharm.,  1876,  502.  On  various  reactions  of  the  blue  oxide  of  molyb- 
denum, see  MASCHKE,  1873. 


52  ALKALOIDS. 

with  aconitine  (yellow  to  brown  or  red,  variable),  codeine 
(orange-yellow),  morphine  (yellow  to  red),  narceine,  narcotine, 
papaperine  (orange),  piperine  (orange),  rhoeadine,  sabadilline 
(yellow),  thebaine,  veratrine.  Red  colors  are  obtained  by  aconi- 
tine (red-brown,  variable),  apomorphine,  berberine  (red  brown), 
brucine  (blood-red),  papaverine  (orange-red),  pseudomorphine 
(orange  red),  physostigmine.  A  Hue  color  is  given  by  colchi- 
cine  and  by  solanine  (Dragendorff).  •  Some  glucosides  give 
briglit  colors ;  ligustrin  and  syringin,  blue  tints. 

Sulphuric  acid  (concentrated),  followed  by  a  minute  addi- 
tion of  nitric  acid  (s.g.  1.40-1.42),  or  of  solid  potassium  nitrate.1 
No  color  is  given  by  atropine,  caffeine,  cinclionidine,  cinchonine, 
nicotine,  pilocarpine,  quinidine,  quinine,  staphysa^rine,  strych- 
nine, theobromine.  Red  colors  are  given  by  brucine,  curarine, 
narcotine  (red- violet),  nepaline,  physostiginine,  sabadilline,  the- 
baine, veratrine  (gradually,  cherry-red).  A  violet  color  is  given 
bv  morphine  (under  directions  specified  for  that  alkaloid).  Co- 
deine gives  a  succession  of  colors,  as  also  does  colchicine. 

Sulphuric  Acid  and  Cane  /Sugar.'2 — The  substance  to  be 
tested,  in  the  dry  state,  is  mixed  with  6  to  8  parts  of  cane-sugar, 
and  a  few  milligrams  of  the  mixture  are  placed  upon  a  drop  or 
two  of  concentrated  sulphuric  acid,  over  a  white  ground.  The 
gradual  browning  of  the  sugar  itself  is  disregarded,  and  will  be 
covered  by  the  briglit  colors  of  characteristic  reactions.  No 
colors  are  given  by  atropine,  brucine,  caffeine,  cinchoriidine,  cin- 
chonine, conine,  nicotine,  quinidine,  quinine,  strychnine,  and 
theobromine.  Reddish  colors  are  given  by  codeine,  curarine, 
gelseminine,  morphine  (purple-red,  then  blue- violet,  dark  blue- 
green,  and  lastly  blackish-yellow — limit  0.0001  to  0.00001  gram), 
nepaline  (gradually),  sabadilline  (reddish-violet).  KlluisJi  color 
by  veratrine. — Various  oils,  and  albuminoids,  give  bright  colors 
with  sulphuric  acid  and  sugar. 

Hydrochloric  Acid,  concentrated,  gives  colors  with  only  a 
few  alkaloids.  Reddish  colors  are  given  by  physostigmine, 
sabadilline,  and  veratrine. 

1  ERDMANN,  1861:  Ann.  Pharm.   Chem..   120;   Zeitsch.  anal.  Chem.,  I, 
224.     Erdmaim  mixed  six  drops  of  nitric  acid  of  s.g.  1.25  with  100  c.c.  of 
water,  and  added  ten  drops  of  this  mixture  to  20  grains  of  sulphuric  acid.     Of 
this — "  Erdmann's  reagent " — 8  to  20  drops  were  added  to  1  or  2  milligrams  of 
the  solid  to  be  tested,  and  the  color  noted  after  |  to  ^  hour. — HUSEMANN,  1863 : 
Ann.  Chem.  PJiar.,    128,  303 — the  well-known  test  for  morphine.     DRAGEN- 
DORFF, 1868:  "Ermittelung  von  Giften,"  p.  239. 

2  SCHNEIDER,   1872:    Ann.  Phys.   Chem.  Pogg.,    147,  128;  Zeitsch.  anal. 
Chem.,     12,     218.      Respecting     reactions     with    substances    not    alkaloids, 
SCHULTZE,  Ann.  Chem.  P/iar.,  71,  266. 


MICROSCOPICAL   CHARACTERISTICS.  53 

Other  Reagents  for  alkaloids  as  a  class,  or  for  groups  of  alka- 
loids.— Iodine  in  hydriodic  acid,  gold  bromide,  sodium  gold 
thiosulphate,  potassium  gold  iodide,  lead  tetra-chloride,  and 
manganese  perhydroxide  in  sulphuric  acid,  were  reported  upon 
by  F.  SELMI  in  1877.  Perchloric  acid,  FEAUDE,  1879-1880. 
Sodium  arseniate  with  sulphuric  acid,  TATTEBSALL,  1879.  Cu- 
pric  ammonium  hydrate,  NADLEE,  1874.  Ferric  chloride  and 
sulphuric  acid,  How,  1878.  Fused  antimonious  chloride, 
SMITH,  1879.  Nitroferricyanide  of  sodium,  as  a  precipitant, 
HOESLEY,  1862. 

The  Microscopical  Characteristics  of  alkaloids,  in  their 
various  combinations,  receive  attention  to  some  extent  in  all 
chemical  literature  upon  these  bodies,  and  in  the  description  of 
the  several  alkaloids  in  this  work.  Among  the  special  contri- 
butions are  the  following :  HELWIG,  1865 :  "  Das  Microscop  in 
Toxicologie."  GODEFFEOY  and  LEDEEMANN,  1877 :  on  cinchona 
alkaloids.  WOBMLEY,  1885  :  "  Microchemistry  of  Poisons,"  2d 
ed.,  Philadelphia.  A.  PEECY  SMITH,  1886  :  identification  of  alka- 
loids by  crystallization  under  the  microscope,  Analyst,  II,  81. 

On  Micro  sublimation  of  Alkaloids  :  HELWIG,  1864:  Zeitsch. 
anal.  Chem.,  3,  43;  "Das  Microscop  in  Toxicologie,"  1865. 
GUY,  1867  :  Phar.  Jour.  Trans.,  [2],  8,  718  ;  9,  10,  58, 106, 195, 
370;  "  Forensic  Medicine,"  London,  1875.  STODDAET,  1867. 
ELLWOOD,  1868.  BLYTH,  1878  :  Jour.  Chem.  Soc.,  33,  313.  In 
this  work,  see  under  Caffeine. — The  Subliming  Cell  of  Dr.  Guy, 
improved  by  Blyth,  consists  essentially  of  a  ring  of  glass,  about 
J  inch  in  thickness,  or  from  J  to  f  inch.  This  glass  ring  rests 
on  an  ordinary  "  cover-glass  " — a  thin  disc  used  under  this  name 
in  microscopy.  Another  cover-glass  is  placed  upon  the  ring, 
which  is  of  a  diameter  to  fit  the  cover- glasses,  and  with  them  make 
a  closed  cell.  The  ring  can  be  made  of  a  section  of  glass  tubing 
by  grinding  the  edges.  The  cell,  so  constituted,  was  heated  by 
Dr.  Guy  through  a  brass  plate  on  which  it  rested.  Dr.  Blyth 
prefers  to  rest  the  cell  upon  liquid  metal,  using  mercury  for  tern 
peratures  below  about  100°  C.,  and  fusible  metal  for  tempera- 
tures above  this  point.  The  liquid  metal  is  contained  in  a 
porcelain  capsule  of  about  3  inches  diameter,  supported  on  the 
ring  of  a  retort-stand,  and  heated  directly  by  the  flame.  A  flask 
of  suitable  size,  from  which  the  bottom  has  been  removed,  is 
placed  over  the  capsule,  upon  the  ring  of  the  retort-stand,  and 
made  to  carry  the  thermometer,  held  in  a  perforated  stopper  and 
with  its  bulb  immersed  in  the  liquid  metal  by  the  side  of  the 
subliming  cell. — A  minute  speck  of  the  article  tested  is  placed 


54  ALOINS. 

on  the  lower  disc  of  the  cell.  Blyth's  definition  of  a  sublimate 
is  this  :  "  The  most  minute  films,  dots,  or  crystals,  which  can  be 
observed  by  a  quarter-inch  power,  and  which  are  obtained  by 
keeping  the  subliming  cell  at  a  definite  temperature  for  sixty 
seconds." 

ALOINS. — Varieties  of  a  neutral  crystalline  principle  ob- 
tained from  the  several  kinds  of  aloes.  As  first  described 
(T.  &  H.  SMITH,  1851),  it  was  obtained  from  Barbadoes  aloes,  and 
was  the  body  now  named  barbaloin.  There  have  been  described  : 

SOMMARUGA  and 

Aloes.                          Yield.1  EGGEB,  1874. 

Barbaloin        Barbadoes        20-25  per  cent. ,  at  most,  CiTH2o07 

TILDEN,  1872. 

Nataloin          Xatal                 16-25  percent.,  at  most,  Ci6H1807 

Socaloin           Socotrine          3  per  cent,  average,  CisHieOr 
Zanzibar           PLENGE,  1885. 

TILDEN  ascribes  to  barbaloin  the  formula  C34H36Oi4 .  H2O, 
and  to  nataloin  C35H28O1;L ;  and  FLUCKIGER  (1871)  obtained  for 
socaloin  C34H38O15 .  5H2O. 

Aloins  are  identified  by  their  color-reactions  with  nitric  and 
sulphuric  acids,  by  which,  also,  and  by  production  of  chrysammic 
acid,  they  are  distinguished  from  each  other  (d).  ALOES  is 
found  in  mixtures  by  treatment  with  acids,  or  by  extraction  with 
amyl  alcohol  and  treatment  with  various  reagents  (d,  p.  55). 
Chrysammic  Acid,  p.  56.  As  to  physiological  effects,  with 
reference  to  valuations,  5,  p.  55. 

a. — Barbaloin,)  crystallized  from  a  concentrated  aqueous 
solution  of  Barbadoes  aloes,  appears  in  tufts  of  small  yellow 
prisms,  losing  2.69  per  cent,  of  water  by  drying  at  100°  C.  or  in 
vacuum.  Nataloin  exists  in  a  crystalline  state  in  Natal  aloes, 
from  which  it  is  left  on  treating  with  an  equal  portion  of  alcohol 
at  48°  C.  or  under,  and  when  recrystallized  forms  thin,  brittle, 
rectangular  scales  with  some  of  their  angles  truncated.  It  loses 
no  water  at  100°  C.  Socaloin  exists  in  Socotrine  or  Zanzibar 
aloes  in  prisms  of  good  size  ;  when  recrystallized  from  methyl 
alcohol,  tufted  acicular  prisms,  which  may  be  obtained  2  to  3 
millimeters  long.  At  100°  C.  it  loses  about  12  per  cent,  of 
water. 

b. — Aloins  are  without  odor  and  have  the  taste  of  aloes. 
Their  purgative  power  has  been  questioned,  and  while  they  have 

1  Of  18  varieties  of  aloes,  yields  of  from  2.2  to  31.3  per  cent,  were  ob- 
tained: DRAGENDORFF,  1874:  "  Werthbestimmung." 


ALOINS.  55 

had  some  little  medicinal  use  as  therapeutic  representatives  of 
aloes,  more  in  Great  Britain  than  elsewhere,  yet  this  use  has  not 
extended,  although  aloin  is  more  agreeable  for  administration 
than  the  aloes  from  which  it  is  extracted.  DRAGENDORFF  states 
(1874: :  "  Werthbestimmung "),  on  experimental  data,  that  (1) 
the  resins  of  any  variety  of  aloes,  separated  as  insoluble  in  cold 
water,  in  doses  of  0.35  gram  (5  to  6  grains),  prove  inactive ; 
(2)  that  perfectly  pure  aloins,  in  doses  of  0.3  to  0. 5  gram  (5  to  7 
grains),  prove  inactive  with  many  persons ;  and  (3)  that  the  so- 
called  aloes-bitter,  soluble  in  cold  water  and  containing  either 
amorphous  aloin  or  oxidized  products,  represents  the  activity  of 
the  drug ;  also  (4)  that  the  purgative  power  of  an  aloes  is 
measured  by  the  quantity  of  bromaloin  precipitated  from  an 
aqueous  solution  of  the  drug,  also  by  the  quantity  of  precipi- 
tate by  tannic  acid.  Dragendorff  infers  that  aloin  is  converted 
into  bodies  having  the  purgative  action  of  aloes.  TILDEN  (1876) 
found  that  all  three  aloins  are  decidedly  uncertain  and  variable 
in  their  action,  and  seem  to  present  no  advantage  over  an  equal 
dose  of  aloes,  except  perhaps  that  griping  was  rather  less  com- 
mon under  their  use. 

c. — The  aloins  are  soluble  in  water,  barbaloin  the  most  freely 
of  the  three,  socaloin  in  about  90  parts,  and  nataloin  very  spar- 
ingly. Alcohol  dissolves  all  the  aloins,  socaloin  requiring  about 
30  parts,  and  nataloin  about  60  parts  (230  parts  absolute  alcohol). 
In  ether  aloins  are  but  slightly  soluble,  though  socaloin  dissolves 
in  about  380  parts.  Aloin  "  from  the  different  varieties  of 
aloes  "  is  described  in  Br.  Ph.  (1885)  as  "  sparingly  soluble  in 
cold  water,  more  so  in  cold  rectified  spirit,  freely  soluble  in  the 
hot  fluids.  Insoluble  in  ether." 

d. — Nitric  acid  (s.g.  near  1.40  or  1.42),  applied  to  the  dry 
aloin  on  a  porcelain  slab,  gives  a  bright  red  color  with  barbaloin 
or  nataloin,  not  with  socaloin.  The  crimson  red  of  barbaloin 
fades  quickly  ;  the  blood  red  of  nataloin  does  not  fade  unless 
heated  (HISTED,  1871 ;  TILDEN,  1876).  Boiling  with  nitric  acid 
produces  chrysammic  acid,  C14H4(NO2)4O2  (tetranitrodioxyan- 
thraquinone),  of  intense  red  color,  from  both  barbaloin  and 
nataloin,  not  from  socaloin.  Oxalic  and  picric  acids,  in  addition, 
are  obtained  from  barbaloin  by  action  of  boiling  nitric  acid 
(distinction  from  socaloin  or  nataloin).  If  nataloin  be  wet  with 
concentrated  sulphuric  acid,  and  then  touched  by  the  vapor  of 
strong  nitric  acid  from  a  glass  rod  or  by  a  minute  fragment  of 
potassium  nitrate,  a  fine  blue  color  is  obtained  (distinction  from 
barbaloin  or  socaloin).  Concentrated  sulphuric  acid,  applied  to 


56  AMYGDALIN. 

the  dry  substance,  and  followed  by  a  minute  fragment  of  potas- 
sium dichromate  (as  in  the  fading- purple  test  for  strychnine), 
causes  a  green  or  greenish-purple  color,  changing  to  greenish- 
yellow. — Alkalies  cause  the  decomposition  of  aloins.  Solu- 
tions of  aloes,  too,  lose  their  bitterness  and  their  purgative 
power  when  made  alkaline  (G.  MCDONALD,  1885). 

CHEYSAMMIC  ACID  (see  above)  crystallizes  in  gold-glittering 
needles,  or  in  yellow  fern-leaves  resembling  picric  acid.  It  de- 
tonates on  heating.  It  is  acidulous  in  reaction,  and  of  intensely 
bitter  taste.  It  is  insoluble  in  cold  water,  easily  soluble  in  alco- 
hol and  in  ether.  It  forms  colored  salts  with  metallic  lustre. 
Potassium  chrysammate  crystallizes  with  bright  green  lustre,  or 
(from  acid  solutions)  as  bright  crimson  needles  with  a  slight 
golden  reflection. 

ALOES.  If  a  grain  of  aloes  or  dry  mixture  be  dissolved  in  16 
drops  of  strong  sulphuric  acid,  4  drops  of  nitric  acid  (s.g.  1.42) 
added,  and  the  mixture  diluted  with  one  ounce  of  water,  a  deep 
orange  or  crimson  color  will  be  obtained.  On  adding  ammonia 
the  color  changes  to  a  claret.  All  substances  containing  chry- 
sammic  acid  behave  nearly  the  same  in  this  test,  except  that 
they  turn  pink  on  adding  ammonia  directly  to  their  aqueous 
solutions,  while  the  solutions  of  aloes  do  not  (Cmpps  and  DY- 
MOND,  1885). — If  a  fluid  containing  aloes  be  extracted  with  amyl 
alcohol,  the  residue  left  by  evaporating  this  solvent  will  have  a 
bitter  taste,  and  when  this  residue  is  dissolved  in  water  the  solu- 
tion will  give  precipitates  with  bromine  in  potassium  bromide 
solution,  basic  lead  acetate,  mercurous  nitrate,  and  tannic  acid, 
and  will  reduce  gold  chloride  and  Fehling's  solution.  The  dry 
residue  will  give  a  blood-red  color  with  potassium  cyanide  and 
hydroxide  (!)KAGENDOEFF,  LENZ,  1882). 

AMYGDALIN.  Co0H27NOn  =  457  (LiEBia  and  WOHLER, 
1837).  ^H^O^OHVp^.CN  (SCHIFF,  1870).— A  gluco- 
side  which  occurs  in  the  bitter  almonds  and  in  numerous  other 
plants  which  yield  hydrocyanic  acid  by  natural  fermentation. 
The  bitter  almonds,  after  removal  of  the  oil  by  pressure,  are  di- 
gested twice  with  hot  95$  alcohol,  and  allowed  to  stand  for  some 
time.  The  alcohol  is  decanted  and  concentrated  to  a  syrup,  from 
which  the  amygdalin  is  precipitated  by  ether.  The  precipitated 
amygdalin  is  washed  with  ether  and  recrystallized  from  boiling 
alcohol. 

Amygdalin  crystallizes  from  alcohol  in  colorless  scales  anhy- 
drous or  with  2H2O,  from  water  in  transparent  prisms,  becoming 
opaque  in  the  air,  and  containing  3H2O.  It  becomes  anhydrous 


ARBUTIN.  57 

at  110-120°  C.  It  is  odorless,  of  a  slightly  bitter  taste  and 
neutral  reaction,  and  rotates  the  plane  of  polarization  to  the 
left.  It  is  soluble  in  any  proportion  of  hot  and  12  parts  cold 
water;  in  11  parts  boiling  and  904  parts  cold  alcohol  (s.  g. 
0.819)  ;  in  12  parts  boiling  and  148  parts  cold  alcohol  (s.  g.  0.939)  ; 
insoluble  in  ether.  Concentrated  sulphuric  acid  dissolves  it 
with  violet-red  color,  which  turns  black  on  warming.  The  other 
mineral  acids  decompose  it.  In  contact  with  emulsin  and  water 
(10  parts  amygdalin,  1  part  emulsin,  and  100  parts  water)  it  is- 
changed  into  benzoic  aldehyde  (oil  of  bitter  almonds),  hydrocya- 
nic acid,  and  glucose,  as  follows  : 


Through  farther  change  of  the  hydrocyanic  acid,  formic  acid 
also  is  formed.  By  boiling  with  dilute  sulphuric  acid  the  same 
reaction  takes  place,  when  formic  acid  is  always  formed.  17 
parts  of  anhydrous  amygdalin,  or  about  24  to  25  parts  (theoretical- 
ly, 19  parts)  of  the  ordinary  commercial  amygdalin,  yield,  when 
fermented  with  emulsin,  one  part  hydrocyanic  acid  and  8  parts 
bitter-  almond  oil.  Boiling  amygdalin  with  aqueous  alkalies  or 
baryta  changes  it  to  ammonia  and  amygdalic  acid  (C20H26O12). 

ANALYSIS,  ELEMENTARY.  See  ELEMENTARY  AN- 
ALYSIS. 

ANALYSIS  OF  PLANTS.     See  PLANT  ANALYSIS. 
ANALYSIS,  ORGANIC.     See  ORGANIC  ANALYSIS.     • 

ARBUTIN.  C12H16O7  =  272.—  A  glucoside  found  (about 
3.5$)  in  the  leaves  of  the  bearberry  (Arctostaphylos  Uva-ursi) 
and  in  a  number  of  other  plants,  especially  in  those  belonging  to 
the  order  Ericacese.  It  may  be  obtained  by  precipitating  the 
decoction  with  lead  subacetate,  freeing  the  filtrate  from  lead  by 
hydric  sulphide,  treating  with  animal  charcoal,  and  crystallizing. 

Crystallizes  in  bunches  of  silky  needles  which  have  the  com- 
position (C12H16O7)2.H2O.  They  become  anhydrous  at  100°  C. 
and  melt  at  170°,  have  a  bitter  taste  and  neutral  reaction. 
Sparingly  soluble  in  cold  water,  readily  soluble  in  hot  water 
and  in  alcohol;  slightly  soluble  in  ether.  Boiled  with  dilute 
sulphuric  acid,  or  subjected  to  the  action  of  emulsin  or  another 
ferment  contained  in  the  bearberry,  it  is  converted  into  hydro- 
quinone,  C6H6O2,  and  glucose.  Treated  with  manganese  diox- 
ide and  sulphuric  acid,  it  is  oxidized  to  quinone,  C6H4O2,  and 
formic  acid.  It  does  not  reduce  alkaline  cupric  solution,  and  is 


$8  ASPARA  GIN—BEBIRINE  . 

not  precipitated  by  salts  of  the  metals.  Concentrated  sulphuric 
acid  dissolves  it  without  color.  Nitric  acid  turns  it  black,  gradu- 
ally dissolving  it  to  a  yellow  solution.  If  an  aqueous  solution  be 
rendered  alkaline  with  ammonia  and  then  phosphomolybdic  acid 
added,  it  becomes  blue  [one  part  in  140,000  parts  water  gives  a 
distinct  color  —  JUNGMANN,  1871  :  Am.  Jour.  Phar.,  43,  205]. 

ARICINE.     See  CINCHONA  ALKALOIDS. 


ASPARAGIN.  CJIgNgOg^lSS.—  Amido-succinamic  Acid. 
Exists  already  formed  in  asparagus  (Asparagus  qfficinalis)  and  a 
great  many  other  plants.  It  crystallizes  from  the  cold-water  ex- 
tract of  asparagus  upon  concentration  to  a  thin  syrup,  and  may 
be  purified  by  treatment  with  animal  charcoal  and  recrystalliza- 
tion  from  hot  water. 

The  crystals  are  hard,  brittle,  transparent  prisms  of  the  tri- 
metric  system  having  the  composition  C4H8N2O3  .  H2O.  They  are 
odorless,  have  a  slight,  disagreeable  taste,  are  permanent  in  the 
air,  and  become  anhydrous  at  100°  C.,  above  which  temperature 
they  are  decomposed.  Asparagin  is  soluble  in  58  parts  cold  and 
4.4  parts  boiling  water  ;  in  500  parts  cold  and  40  parts  boiling 
60$  alcohol  ;  in  700  parts  boiling  98$  alcohol  ;  insoluble  in  abso- 
lute alcohol,  chloroform,  ether,  and  benzene  ;  easily  soluble  in 
acids  and  aqueous  alkalies.  It  forms  weak  compounds  with  both 
acids  and  alkalies.  In  contact  with  the  accompanying  extractive 
substances,  yeast  or  casein,  etc.,  it  is  changed  by  fermentation 
into,  succinate  of  ammonium  (sometimes  with  the  intervening 
formation  of  aspartate  of  ammonium).  When  boiled  with  acids 
or  alkalies  it  is  resolved  into  aspartic  acid  (C4HTN'O4)  or  amido- 
succinic  acid,  and  ammonia. 

Respecting  the  quantitative  estimation  of  asparagin,  see  the 
current  reports  of  E.  SCHULZE,  1881  to  1885. 

ATROPINE.     See  MIDKIATIC  ALKALOIDS. 
BAKING   POWDERS.     See  TAKTAKIC  ACID. 

BEBIRINE.  Biberine,  Ci8H21NO3,  dried  at  100°  C.—  In 
Greenhart  or  Bibirin  bark  (British  Guiana),  H.  EODIE,  1835  ;  as 
"JBuxine"  in  bark  of  Buxus  sempivirens  or  Common  Box, 
Faury,  1830,  identified  with  bebirine  by  Walz  in  1860  and 
Fliickiger  in  1869  ;  as  Pelosin,  in  Pareira  Brava  root  (Chon- 
drodendron  tomentosum  and  Cissampelos  Pareira),  Wiggers,  1839, 
identified  with  bebirine  by  Fliickiger  in  1869. 


BEN  ZOIC  ACID.  59 

a. — A  white,  amorphous  powder,  melting  at  about  145°  C., 
and  decomposing  at  a  higher  temperature.  Its  salts  of  common 
acids  are  uncrystallizable,  pulverulent  or  resinous,  and  white  or 
yellowish- white. 

#. — The  alkaloid  and  its  common  salts  are  odorless,  with  a 
strong  and  persistent  bitter  taste.  Its  effect  is  held  to  resemble 
that  of  quinine,  and  is  given  in  about  the  same  quantities. 

c. — Very  slightly  soluble  in  water  (6600  parts  cold,  1500 
boiling)  ;  soluble  in  5  parts  absolute  alcohol  and  13  parts  of  ether ; 
soluble  in  chloroform,  benzene,  amyl  alcohol,  and  carbon  disul- 
phide.  Its  solutions  are  strongly  alkaline  to  test-papers.  The 
sulphate,  hydrochloride,  and  acetate  are  readily  soluble  in  water ; 
the  solutions  having  a  neutral  reaction. 

d. — The  alkali  hydrates  and  carbonates  give  precipitates, 
soluble  in  excess  of  the  hydrates.  Precipitates  are  caused  by 
potassium  mercuric  iodide  (white),  potassium  iodide,  mercuric 
chloride,  gold  chloride  (yellow- white),  platinic  chloride  (pale  yel- 
low), and  sodium  phosphomolybdate  (dissolved  blue  by  ammo- 
nia, decolored  by  boiling),  picric  acid  (yellow),  sulphocyanate 
(reddish-white).  Nitric  acid  dilute  and  potassium  nitrate 
give  a  white  precipitate  (Fliickiger);  sodium  phosphate,  a  white 
precipitate.  The  pure  alkaloid  does  not  reduce  iodic  acid. 

e. — Bebirine  has  been  prepared  from  the  different  plants  in 
which  it  occurs,  by  extraction  with  acidulated  water,  and  precipi- 
tation with  soda  or  ammonia,  with  a  precipitate  by  lead  subacetate 
and  extraction  therefrom  by  dilute  sulphuric  acid  (or  by  digesting 
the  precipitate  with  magnesia  and  extracting  with  alcohol  or  ether). 
Purification  by  animal  charcoal  is  sometimes  used  instead  of,  or 
after,  the  lead  precipitation  ;  the  object  in  either  operation  being 
chiefly  removal  of  resinous  matter. 

f. — The  precipitated  alkaloid  loses  8.2  p.  c.  water  (near- 
ly IfHgO)  at  100°  C.— Bebirine  platinic  chloride  (C18H21NO3)2 
(HCl)QPtCl4  (Bddeker).— The  Hydrochloride  is  C18H21NO3 .  HC1. 
—The' Sulphate  (C18H21NO3)2H2SO4  [Maclagen]. 

BENZOIC  ACID.  Benzoesaure.  Acide  Benzoique. 
CLH6O2=:122  (monobasic).  C6H5.CO2H.  Carboxyl-benzene. 
Without  isomers. — Sources: — Benzoic  acid  is  found,  uncom- 
bined,  in  the  proportion  of  10  to  19  per  cent.,  in  Benzoin,  the 
balsamic  resin  of  Styrax  Benzoin,  produced  in  Siam  and  Suma- 
tra ;  also  in  smaller  proportions  in  Balsam  of  Peru,  in  Balsam  of 


60  BEN  ZOIC  ACID. 

Tolu  ?  (Bussy,  1876),  in  fruit  of  Yaccinium  vitis-idaea  (cowberry) 
(O.  Low,  1879),  and  in  the  Xanthorrhcea  resins.  It  has  been 
found  in  certain  plums  and  other  fruits.  In  combination  with 
ethereal  bases,  forming  essential  oils,  it  is  found  in  numerous  bal- 
sams and  resins,  and  in  the  oils  of  cinnamon,  bergamot,  origa- 
num, and  cananga  (ylang-ylang).  The  fragrant  oil  slightly  per- 
vading the  Benzoin  is  reported  to  be  ethyl  benzoate.  The 
benzoates  frequently  accompany  or  substitute  the  compounds  of 
cinnamic  acid,  and  sometimes  occur  with  coumarin.  The  suint 
of  sheep's  wool  contains  benzoates  (TAYLOK,  1876).  Benzoic  acid 
is  slowly  formed  by  the  atmospheric  oxidation  of  oil  of  bitter 
almond  (benzoic  aldehyde),  appears  among  the  oxidation-products 
of  cinnamic  acid  and  various  aromatic  compounds,  and  results 
from  certain  decompositions  of  albuminoids.  SCHULZE  (1885) 
finds  benzoic  acid  in  the  heavier  (phenol -containing)  coal-tar  oils. 
Hippuric  acid,  in  decomposing  urine,  may  change  to  benzoic 
acid. 

Benzoic  acid  is  manufactured  (1)  from  Benzoin,  either,  as 
"flowers  of  benzoin,"  by  direct  sublimation,1  or  in  the  wet  way, 
as  "crystallized  benzoic  acid,"  by  dissolving  with  lime,  precipi- 
tating from  the  calcium  benzoate  solution  by  adding  hydrochloric 
acid,  and  recrystallizing  from  hot  water  to  remove  resin.  (2) 
From  the  Hippuric  acid  of  graminivorous  animals,  chiefly  horses 
and  cows,  by  concentrating  the  urine,  acidulating  with  hydro- 
chloric acid  to  obtain  crystallized  hippuric  acid,  and  boiling  the 
latter  with  crude  hydrochloric  acid,  when  benzoic  acid  and  the 
by-product  glycocoll  are  promptly  formed  : 

CH2 .  KE(CO .  C6H5) .  CO2H+H9O 

=C6H5C02H+CH2 .  NH3 .  C02H 

(3)  From  the  coal-tar  product,  Naphthalene,  C10H8,  which  by 
treatment  with  nitric  acid  is  converted  into  phthalic  acid, 
C6H4(CO2H)2,  when  the  latter,  heated  to  about  350°  C.  with  its 
equivalent  of  calcium  hydrate,  in  absence  of  air,  forms  the  lime 
salt  of  benzoic  acid : 

2C6H4(CO2)2Ca+Ca(OH)2=(C6H5C02)2Ca+2CaCO3. 
And  (4)  from  Toluene,  of  the   coal-tar  distillates,  C6H5.OH3, 
known  as  toluol,  by  formation  of  trichloro-toluenes  (C6H5 .  CC13), 
and  conversion  of  the  latter  to  benzoic  acid.     The  pharmaco- 
poeias require  the  "  natural  benzoic  acid."    Of  "  artificial  benzoic 

1  LOEWE,  1869,  and  Eump,  1878,  maintain  that  part  of  the  benzoic  acid 
obtained  is  not  ready  formed  in  the  benzoin,  but  requires  to  be  separated  from 
some  combination,  or  union  with  another  acid.  The  combination  with  cinna- 
mic acid,  3C7H6Oa .  C9H802,  has  been  reported. 


BENZOIC  ACID.  61 

acid  "  the  production  from  toluol  is  increasing,  and  little  is  made 
from  phthalic  acid.     (See,  further,  under  Impurities.) 

BENZOIC  ACID  may  be  identified  by  its  behavior  in  sublima- 
tion (#),  toward  solvents  and  precipitants  (c),  in  reduction  to  bit- 
ter-almond oil,  and  in  its  reaction  with  ferric  salts  (d).  From 
Cinnamic  acid  it  is  distinguished  by  not  being  oxidized  to  bitter- 
almond  oil  (g) ;  from  Salicylic  acid  by  the  color  of  the  ferric 
salt.  It  may  be  separated  (e)  by  distillation  of  the  free  acid  (2) 
or  from  its  salts  (1) ;  by  solution  in  solvents  not  miscible  with 
water  (3) ;  by  precipitation  as  free  acid  from  aqueous  solution  of 
its  salts  (4) ;  by  sublimation  (5) ;  from  cinnarnic  acid  (T) ;  from 
milk  (8)  (p.  65).  It  can  be  estimated  by  acidimetry,  and  by 
weight  of  the  free  acid,  or  its  lead  salt  (f).  Directions  for  ex- 
amination are  given  (g)  as  to  impurities,  accompaniments,  and 
required  quality  for  specific  uses,  and  with  regard  to  the  sources 
of  its  production. 

a. — Benzoic  acid  appears  in  pearly,  lustrous,  friable,  and  flexi- 
ble plates  or  needles,  or  in  flocculent  masses  of  plate -like  or  nee- 
dle-form structure,  of  hexagonal  outline.  From  dilute  alcohol 
six-sided  prisms  are  obtained.  The  pure  acid  is  colorless  or 
white ;  that  sublimed  from  benzoin  is  frequently  yellowish  to 
yellowish-brown,  and  this  coloration  is  requisite  in  the  descrip- 
tion of  the  German  pharmacopoeia.  The  coloration  deepens  in 
long  keeping.  (See  g.)  The  pure  acid  is  permanent  in  the 
air.  Specific  gravity,  1.292,  at  mean  temperature  compared  with 
water  at  4°  C.  (SCHRCEDEK,  1880).— It  melts  at  121°  C.  (CAR- 
NELLY,  1878),  and  (by  same  authority)  boils  at  249°  C.  (480.2°  F.), 
subliming  unchanged.  But  at  100°  C.,  either  dry  or  with  steam, 
it  vaporizes  perceptibly,  and  its  vapor  irritates  the  throat  and  ex- 
cites coughing.  By  direct  heat,  alone,  as  in  a  test-tube  moved 
over  a  flame,  it  vaporizes  without  residue,  the  sublimate,  if 
slowly  deposited,  crystallizing  in  needles.  The  vapors  redden 
litmus  paper.  From  benzoates  heated  with  phosphoric  acid,  or 
bisulphate,  the  same  vapors  and  sublimate  may  be  obtained. 
Benzoic  acid  is  carried  over,  to  some  extent,  with  vapor  of  alco- 
hol, benzene,  and  other  solvents  of  low  boiling  points.  Boiled 
with  strong  alkalies  in  aqueous  solution  it  suffers  change. 

~b. — Benzoic  acid  has  a  sharp,  acid  taste,  and  when  pure  is 
without  odor.  The  pharmacopoeia!  acid,  from  benzoin,  has  an 
agreeable  aromatic  odor,  slight  in  the  acid  by  precipitation, 
strong  in  the  acid  by  sublimation,  sometimes  resembling  vanilla, 
and  by  authority  of  the  Ph.  Germ,  somewhat  empyreumatic. 


62  BEN  ZOIC  ACID. 

That  from  toluol  often  has  an  almond  odor ;  that  from  hippuric 
acid  a  urinous  odor. — The  medicinal  dose  of  benzoic  acid  does 
not  overgo  20  grains.  Locally  it  sometimes  causes  mucous  irri- 
tation.— -In  the  human  body  benzoic  acid  is  converted  into  hip- 
Suric  acid,  the  reaction  being  the  reverse  of  that  given  above 
3.  60),  and  excreted  in  the  urine.  If  large  quantities  of  ben- 
zoic  acid  be  administered,  a  portion  may  be  carried  into  the 
urine  without  change. — Benzoic  acid  is  an  efficient  antiseptic 
and  antiferment,  more  powerful  than  salicylic  acid.  ARCHER 
(1878)  used,  for  infusions,  saccharine  liquids,  etc.,  about  4  grains 
to  one  pound,  or  near  0.06  per  cent.  ECCLES  (1885)  estimates 
about  0.04  per  cent,  to  be  sufficient  for  hypodermic  medicated 
liquids. 

c. — Benzoic  acid  dissolves  in  water  as  follows  (BOURGOIN, 
18T9) :  at  15°  C.  (59°  F.)  in  408  parts ;  at  20°  C.  (68°  F.)  in  345 
parts ;  in  17  parts  of  boiling  water.  In  500  parts  water  of  ordi- 
nary temperature  (Fluckiger*  s  Phar.  Chem.)  In  372  parts 
water  (Phar.  German.)  In  333  parts  at  15°  C.  ;  250  parts  at 
20°  C.  (Hager's  Commentar.,  2d  ed.)  In  2J  to  3  parts  of  al- 
cohol of  ninety  per  cent.  ;  in  2.2  parts  absolute  alcohol ;  in  1 
part  of  boiling  alcohol.  In  2  to  3  parts  of  ether ;  7  to  8  parts  of 
chloroform ;  8  parts  of  benzene.  Freely  in  petroleum  benzin, 
amyl  alcohol,  and  dissolves  in  volatile  oils  and  in  fixed  oils. 

Benzoic  acid  has  a  decided  acid  reaction  to  test-papers,  and 
causes  effervescence  in  aqueous  solutions  of  carbonates.  Carbon 
dioxide  decomposes  alkali  benzoate  in  alcoholic  solution,  causing 
a  precipitate  of  alkali  carbonate. — The  metallic  benzoates  are 
normal  salts  of  a  good  degree  of  stability.  Ferric  benzoate  be- 
comes in  part  basic  in  water,  and  mercurous  benzoate  in.  hot 
water  forms  mercury  and  mercuric  benzoate.  Both  the  normal 
and  basic  lead  salts  are  obtained.  The  normal  benzoates  are 
either  freely  or  moderately  soluble  in  water ;  those  of  lead,  sil- 
ver, and  mercury  being  sparingly  soluble  in  hot  water,  but  pre- 
cipitated by  adding  solutions  of  alkali  benzoate  to  the  metallic 
salt  solutions  in  the  cold.  Alcohol  dissolves  most  benzoates 
sparingly  or  freely  ;  it  decomposes  the  benzoates  of  mercury. 
BENZOATE  OF  SODIUM  crystallizes,  with  one  aq.,  in  slightly  efflo- 
rescent needles ;  from  a  drop  of  alcoholic  solution,  in  microsco- 
pic star-form  groups.  The  salt  dissolves,  with  a  neutral  reac- 
tion, in  about  2  parts  cold  water,  and  in  13  parts  of  90$  alcohol, 
not  in  ether  or  chloroform.  Ammonium  benzoate  crystallizes 
anhydrous ;  it  loses  ammonia  and  acquires  free  acid  when  ex- 
posed to  the  air.  Calcium  benzoate  crystallizes  in  feathery  nee- 


BEN  ZOIC  ACID.  63 

dies,  with  four  molecules  of  water,  efflorescent,  and  soluble  in 
20  parts  of  cold  water. — Cinchonidine  benzoate,  normal,  forms 
short  prisms,  anhydrous,  soluble  in  340  parts  of  water  at  10°  C. — 
Benzoates  of  methyl  and  ethyl  are  colorless,  oily  liquids,  sinking 
in  water,  of  pleasant  and  balsamic  odors,  boiling  respectively  at 
199°  and  212°  C.,  not  more  than  slightly  soluble  in  water,  freely 
soluble  in  alcohol. 

d. — Aqueous  solutions  of  benzoates,  by  addition  of  hydro- 
chloric acid  or  sulphuric  acid,  give  a  voluminous,  crystalline, 
white  precipitate  of  benzoic  acid,  subject  to  its  solubilities  as 
stated  above  (c). — Ferric  chloride  solution,  in  a  neutral  benzoate 
solution,  gives  a  flesh-colored,  voluminous  precipitate  of  basic 
ferric  benzoate,  formed  more  quickly  if  the  reagent  be  slightly 
basic.  The  precipitate  is  not  readily  dissolved  by  acetic  acid. 
Free  benzoic  acid,  in  excess  of  saturated  solution,  is  slowly  pre- 
cipitated by  the  normal  iron  salt.  If  the  solution  tested  be 
strongly  alkaline  in  reaction,  a  misleading  brown  precipitate  of 
ferric  hydrate  may  occur.  The  ferric  succinate  precipitate  is 
red-brown. — Silver  nitrate,  in  neutral  solution  of  a  benzoate, 
forms  a  voluminous  white  precipitate  of  silver  benzoate,  soluble 
in  hot  water,  then  crystallizing  on  cooling,  somewhat  more  solu- 
ble in  alcohol,  dissolved  by  acetic  acid,  also  by  ammonia,  not  ob- 
tained with  free  benzoic  acid. — Acetate  of  Lead,  in  neutral 
solution  of  a  benzoate,  not  too  dilute,  gives  a  white  precipitate 
of  lead  benzoate,  somewhat  soluble  in  excess  of  the  reagent, 
soluble  in  hot  water,  dissolved  by  acetate  of  ammonium,  not  by 
ammonia.  Treatment  with  hydric  sulphide  resolves  the  pre- 
cipitate into  lead  sulphide  and  free  benzoic  acid,  the  latter  being 
separated  by  hot  filtration  or  by  help  of  alcohoL  Also,  if  the 
lead  benzoate  be  boiled  with  a  requisite  quantity  of  sodium  sul- 
phate, transposition  of  the  metals  is  effected,  and  a  filtrate  of  so- 
dium^ benzoate  may  be  obtained. — Barium  chloride  and  calcium 
chloride  give  precipitates  only  in  concentrated  solutions  of  alkali 
benzoates,  but  the  precipitation  is  promoted  by  free  addition  of 
alcohol. 

Metallic  magnesium,  or  aluminium,  or  sodium -amalgam,  in 
solution  of  benzoic  acid  or  benzoate,  acidulated  with  only  enough 
sulphuric  acid  to  cause  a  moderate  evolution  of  hydrogen,  on 
standing  from  half  an  hour  to  several  hours,  effects  the  reduc- 
tion to  benzoic  aldehyde  (C6H5 .  COH),  bitter-almond  oil,  recog- 
nized by  its  odor.  This  distinctive  reduction  is  also  obtained  by 
passing  the  dry  vapors  of  benzoic  acid  through  faintly  ignited 
zinc-dust. — Heated,  with  two  or  three  parts  of  lime  or  with  so- 


64  BEN  ZOIC  ACID. 

dium  or  potassium  hydrate,  in  a  small  distilling  apparatus,  a  dis- 
tillate of  benzene  is  obtained:  C6H5CO2H=G\TH6+COo.— With 
concentrated  sulphuric  acid,  pure  benzoic  is  not  colored,  but  is 
dissolved.  If  glucose  be  present  a  blood-red  color  is  obtained, 
as  noted  under  Salicylic  Acid,  d. — Pure  benzoic  acid  does  not 
discolor  the  permanganate  solution,  nor  reduce  the  potassium 
cupric  (Fehling's)  solution  when  heated,  nor  blacken  ammonia- 
silver  nitrate. 

e. — Separation. — (1)  Water  cannot  be  evaporated  from  free 
benzoic  acid  without  its  serious  waste,  and  it  suffers  a  slight  loss 
in  evaporation  of  its  solutions  in  alcohol,  benzol,  etc.  For  the 
concentration  of  its  aqueous  solution  it  is  to  be  neutralized  by 
adding  just  enough  sodium  carbonate.  Ammonia  is  not  re- 
tained in  full  combination.  (2)  Small  quantities  of  free  benzoic 
acid  may  be  distilled  over  with  water,  and  for  this  purpose  ben- 
zoates  may  be  decomposed  by  adding  enough  sulphuric  acid. 
(3)  Free  benzoic  acid  may  be  obtained  from  any  aqueous  liquid 
by  shaking  with  chloroform,  or  benzol,  or  ether,  or  carbon  di- 
sulphide.  The  separation  is  by  no  means  complete  by  one  appli- 
cation of  the  solvent,  and  the  more  concentrated  the  aqueous 
solution  the  better.  The  chloroform  or  ether  is  caused  to  evapo- 
rate from  the  benzoic  acid  spontaneously  or  by  a  current  of  air 
from  a  bellows.  Ether  does  not  give  as  dry  a  residue  as  chloro- 
form. If  the  chloroform  or  ether  or  benzol  solution  be  shaken 
with  repeated  portions  of  very  dilute  aqueous  alkali,  the  benzoic 
acid  is  brought  back  into  watery  solution  of  benzoate.  Also, 
ether,  chloroform,  etc.,  may  be  used  upon  dry  materials,  in  sepa- 
rations of  benzoic  acid.  (4)  Precipitation,  in  a  concentrated 
aqueous  solution,  by  hydrochloric  acid,  collecting  the  precipitate 
after  standing  and  at  the  coolest  practicable  temperature,  is  a 
convenient  method  of  separation.  The  mother-liquid,  or  filtrate, 
may  be  shaken  with  chloroform  to  recover  the  acid  remaining 
in  aqueous  solution.  Materials  such  as  benzoin  resin  may  be  di- 
gested with  some  excess  of  lime  or  alkali,  and  the  filtrate  of 
aqueous  benzoate  precipitated  with  acid,  as  in  the  manufacture  of 
natural  benzoic  acid  in  the  wet  way.  (5)  The  finely  divided  ma- 
terial may  be  heated,  dry,  for  sublimation.  In  preparing  the 
sublimed  medicinal  acid,  the  vapors  are  made  to  rise  from  a  wide 
dish,  through  a  porous  paper  diaphragm,  and  are  collected  upon 
the  inner  surface  of  a  cone  of  sized  paper,  the  edges  being  fitted 
or  pasted  close.  The  temperature  of  the  sand-bath,  or  iron  plate, 
should  be  kept  some  time  at  about  145°  C.  (293°  F.),  and  gradu- 
ally raised  at  the  close  to  200°  C.  (392°  F.),  the  operation  requir- 


BENZOIC  ACID.  65 

ing  from  one  to  four  hours.  A  second  sublimate  may  be  ob- 
tained after  pulverizing  the  fused  material  and  taking  a  fresh 
diaphragm.  The  Ph.  Fran,  directs  the  addition  of  an  equal 
weight  of  sand  to  the  powdered  benzoin.  An-  analytic  sublima- 
tion, for  separation  from  fixed  impurities  may  be  conducted  in 
a  pair  of  clamped  watch-glasses  with  ground  edges  well  fitted,  or 
closed  with  a  narrow  ring  cut  out  of  thin  asbestos  cloth.  (6) 
Precipitation  with  lead  acetate,  as  indicated  under  d,  serves  the 
demands  of  separation  from  substances  not  forming  insoluble 
lead  compounds.  (7)  From  cinnamic  acid  by  precipitation  of 
the  latter,  in  a  cold  neutralized  solution,  with  manganous  sul- 
phate or  chloride,  avoiding  any  excess  of  this  reagent.  Manga- 
nous benzoate  dissolves  in  about  20  parts  of  water ;  manganous 
cinnarnate  is  but  slightly  soluble  in  water.  Ether  or  chloroform 
solution  separates  free  benzoic  from  hippuric  acid.  (8)  From 
milk,  MEISSL  (1882)  adds  lime  to  alkaline  reaction,  evaporates  to 
one-fourth,  adds  gypsum,  and  dries  on  the  water-bath.  The  dry 
mass,  powdered,  is  extracted  with  alcohol,  after  acidulation  with 
sulphuric  acid.  The  alcoholic  solution  is  neutralized  with  ba- 
ryta, concentrated,  acidulated  with  sulphuric  acid,  and  extracted 
with  ether,  from  which  the  benzoic  acid  crystallizes  almost  pure. 

f. — Quantitative. — Free  benzoic  acid,  in  absence  of  other 
acids,  whether  taken  in  distillates,  or  residues  of  separative  sol- 
vents, or  in  original  materials,  can  be  quite  closely  estimated 
volumetrically  with  a  standard  solution  of  alkali  (BOOKMAN  : 
"  Untersuchungsmethoden,"  1884),  using  litmus  as  the  indicator. 
The  weighed  material  for  estimation  is  treated  directly  with  an 
excess  of  the  volumetric  alkali  measured  from  the  burette,  stirred 
to  bring  all  the  benzoic  acid  into  solution  as  benzoate,  when  the 
liquid  is  titrated  back  with  the  proper  volumetric  acid.  Each 
c.c.  of  normal  solution  of  alkali  (after  deducting  c.c.  of  normal 
solution  of  acid)— 0.122  gram  of  benzoic  acid.  Taking  1.22  gram 
of  the  material,  each  c.c.  of  decinormal  solution  of  alkali  (after 
deducting  for  the  acid  used  in  titrating  back)=l  per  cent,  of 
benzoic  acid. 

Benzoic  acid  may  be  weighed,  directly,  as  C7H6O2.  For  this 
purpose  the  best  form  is  that  of  good  crystals,  either  from  a  so- 
lution or  by  slow  sublimation.  The  residue  obtained  by  spon- 
taneous evaporation,  of  chloroform,  ether,  or  other  separative 
solvent  of  free  benzoic  acid — also  a  clean  precipitate — may  be 
weighed.  The  acid  is  to  be  dried  over  sulphuric  acid,  any  excess 
of  liquid  or  adhering  moisture  being  first  taken  up  with  blotting- 
paper. 


66  BEN  ZOIC  ACID. 

Salts  of  benzole  acid  are  usually  treated  to  obtain  the  free  acid, 
as  above  described  (e),  but  they  may  be  precipitated,  in  a  neutral 
solution,  by  lead  acetate,  as  stated  under  d.  The  lead  benzoate, 
Pb(C7H5O2)2,  is  washed  with  cold  alcohol  acidulated  with  one- 
half  per  cent,  of  acetic  acid,  and  dried  at  100°  C.  The  weight 
multiplied  by  0.5416  gives  the  quantity  of  benzoic  acid. 

gm — Impurities. — Chemically  pure  benzoic  acid  is  precisely 
the  same  in  all  properties,  whether  manufactured  from  the  bal- 
samic benzoin  or  from  urine,  toluol,  or  naphthalene ;  but  a 
chemically  pure  acid  has  not  been  manufactured,  on  a  commer- 
cial scale,  from  any  source.  The  chief  uses  of  benzoic  acid  are 
(1)  in  medicine  and  (2)  in  the  production  of  dyes.  It  is  used, 
also,  for  the  manufacture  of  food  flavors  and  as  an  antiseptic. 
For  medicinal  purposes  the  pharmacopoeias  designate  its  source 
as  follows : 

Ph.  Germ. — "  From  benzoin  by  sublimation  .  .  .  yellowish 
to  yellowish-brown  .  .  .  with  odor  of  benzoin,  somewhat  empy- 
reumatic." 

Br.  Ph. — "  From  benzoin  ...  by  sublimation.  Not  chemi- 
cally pure.  Nearly  colorless." 

Ph.  Fran. — "  From  benzoin  "  prepared  by  alternative  direc- 
tions (1)  by  sublimation,  (2)  by  humid  method. 

U.  S.  Ph. — White  scales  or  needles,  "  having  a  slight  aroma- 
tic odor  of  benzoin." 

There  may  be  two  reasons  for  requiring  medicinal  benzoic 
acid  to  be  sublimed  from  "  the  gum  " :  (1)  the  essential  oil  of 
benzoin  obtained  with  the  sublimed  acid  has  a  stimulant  effect 
and  an  agreeable  odor ;  (2)  by  outlawing  the  artificial  product  the 
injurious  impurities  frequently  present  in  it  may  be  avoided. 
The  artificial  acid,  quoted  as  "  German  benzoic  acid,"  has  been 
for  several  years  priced  at  from  one-third  to  two-thirds  the  value 
of  the  natural  acid,  quoted  as  "English  benzoic  acid."  Un- 
doubtedly chemically  pure  benzoic  acid  will  be  made  from  hip- 
puric  acid  or  from  toluol  (DYMOND,  1883  ;  JACOBSEN,  1881),  and 
furnished  at  prices  lower  tnan  those  for  the  natural  acid.  But 
hitherto,  in  any  production  of  the  artificial  acid  for  medicinal 
uses,  with  little  encouragement  for  open  statement,  there  has  been 
more  effort  to  counterfeit  the  chemical  impurities  of  the  natural 
sublimed  acid  than  to  avoid  the  chemical  impurities  of  the  arti- 
ficial product.  A  chemically  pure  benzoic  acid,  from  any  source, 
is  acceptable  for  the  preparation  of  medicinal  benzoates. 

In  sensible  properties  the  acid  recently  sublimed  from  ben- 


BEN  ZOIC  ACID.  67 

zoin  has  a  white  or  pearl  color  if  sublimed  slowly,  at  tempera- 
ture of  about  125°-140°  C.,  with  rejection  of  the  last  fraction 
of  sublimate,  even  this,  from  some  varieties  of  benzoin,  being 
nearly  colorless.  But  a  sharp  heat,  of  about  200°  C.,  gives  a 
yellowish  sublimate,  becoming  yellowish-brown  in  its  last  por- 
tions, and  in  proportion  to  increase  of  color  is  the  distinctness 
of  empyreumatic  odor  obtained,  in  addition  to  the  proper  ethereal 
and  vanilla-like  odor  of  the  benzoin  obtained  with  colorless  sub- 
limates. The  acid  sublimed  from  Sumatra  or  Penang  benzoin 
has  only  a  faint  odor,  not  vanilla-like.  Any  empyreumatic  oil 
pervading  the  crystals  darkens  gradually  by  action  of  air,  and 
colorless  samples  of  sublimed  benzoic  acid  are  liable  to  acquire  a 
yellowish  tint  on  long  keeping.  Benzoic  acid  well  prepared  in 
the  wet  way  (p.  60)  is  in  water-white  crystals,  larger  and  not  so 
much  in  flocculent  masses  as  the  "  flowers  of  benzoin."  It  has 
but  a  slight  ethereal  odor  of  benzoin,  without  empyreuma.  But 
if  it  has  not  been  crystallized  from  the  precipitate  it  will  contain 
much  resin  of  benzoin,  with  some  color,  and  will  not  dissolve 
clear  in  hot  water. — Artificial  benzoic  acid  i's  frequently  obtained 
in  distinct  prismatic  crystals  of  considerable  size.  That  from 
hippuric  acid  is  apt  to  have  a  horse-stable  odor ;  that  from  to- 
luol, an  odor  of  bitter-almond  oil ;  and  imitated  "  flowers  of 
benzoin  "  may  have  ethereal  or  empyreumatic  odors. 

Cinnamic  acid  is  occasionally  present  in  all  varieties  of  ben- 
zoin. In  sublimation  it  requires  a  higher  heat  than  benzoic  acid, 
and  its  vapors  are  denser.  Sublimed  benzoic  acid  with  empyreu- 
matic odor  and  yellowish-brown  color  is  likely  to  contain  cinna- 
mic  acid,  if  it  were  present  in  the  benzoin.  Benzoic  acid  from 
benzoin  by  the  wet  way  is  by  no  means  likely  to  be  free  from 
cinnamic  acid,  if  this  were  present  in  the  benzoin. 

The  impurities  incidental  to  sources  may  be  enumerated  as 
follows :  In  natural  benzoic  acid  by  sublimation :  Ethereal  oil 
containing  more  or  less  styrol  (cinnamene,  C8H8),  vanillin 
(C8H8O3)  if  prepared  from  the  true  Siamese  benzoin  (JANNASCH 
and  RUMP,  1878),  and  sometimes  empyreumatic  distillate.  Also 
cinnamic  acid. — In  natural  benzoic  acid  by  the  wet  way :  Cin- 
namic acid,  resins,  calcium  chloride,  ethereal  oil. — In  the  product 
from  hippuric  acid  :  Ammonia  or  nitrogenous  bodies  readily 
yielding  it,  substances  giving  the  odor  of  urine  or  of  the  perspi- 
ration of  the  horse,  hydrocyanic  acid  (a  product  of  hippuric 
acid  by  heat),  and  chlorides.— In  toluol-benzoic  acid:  Chloro- 
toluenes,  oil  of  bitter  almond  (benzoic  aldehyde) — which  is  formed 
from  dichloro- toluene,  while  benzoic  acid  results  from  trichloro- 
toluene — ammonium  compounds,  chlorides  and  sulphates. 


68  BEN  ZOIC  ACID. 

Imitated  natural  benzole  acid  is  prepared  by  subliming  from 
a  mixture  of  (odorless)  artificial  benzoic  acid,  and  either  benzoin 
or  the  resinous  residue  after  sublimation  of  the  natural  acid. 
Also,  by  addition  of  ethereal  oils,  etc. 

Tests. — For  cinnamic  acid,  by  its  oxidation,  giving  benzoic 
aldehyde,  with  odor  of  bitter-almond  oil.  One  gram  of  the  acid 
(itself  free  from  almond  odor)  with  half  as  much  permanganate 
of  potassium,  rubbed  in  a  mortar  with  a  few  drops  of  water 
(LT.  S.  Ph.)  A  mixture  of  the  acid  with  equal  quantity  of  the 
permanganate  and  ten  parts  of  water  is  warmed  for  a  short  time 
in  a  test-tube  (Ph.  Germ.)  The  test  is  delicate  and  sufficient, 
but  the  decoloration  of  a  permanganate  solution  has  ho  meaning 
in  the  quest  for  cinnamic  acid. — For  the  ethereal  and  empyreu- 
matic  oils  peculiar  to  natural  benzoic  acid  by  sublimation  (chemi- 
cal impurities  in  evidence  of  medicinal  genuineness),  their  reac- 
tions as  reducing  agents  upon  permanganate,  or  upon  silver  in 
alkaline  solution,  are  resorted  to,  as  follows :  Of  the  saturated 
water  solution,  when  cold,  10  c.c.  are  treated  with  about  10  drops 
of  solution  of  potassium  permanganate  (1  to  1000).  With  the 
true  sublimed  acid  the  color  changes  to  red-brown  and  brown  in 
from  1  to  2  minutes  ;  with  natural  benzoic  acid  by  precipitation 
and  crystallization  the  color  changes  in  4  to  8  minutes ;  with 
various  samples  of  artificial  acid  treated  to  imitate  the  natural 
sublimate,  over  2  minutes  (Hager's  Commentar,  2d  ed.,  59). ' — 
Boil  0.1  gram  of  the  acid  with  3  c.c.  of  water  of  ammonia ;  add 
about  5  drops  of  silver  nitrate  solution,  and  then  drops  of  diluted 
hydrochloric  acid  until  a  permanent  and  decided  turbidity  is 
just  reached  (while  there  is  still  a  very  slight  excess  of  ammonia). 
With  true  sublimed  benzoic  acid  the  slight  precipitate  is  not 
white,  but  yellowish. — Concentrated  sulphuric  acid,  with  a  smaller 
quantity  of  the  benzoic  acid,  gives  a  yellowish  color  with  the 
sublimed  acid,  becoming  brown  at  150°  C. ;  while  at  this  high 
temperature  the  chemically  pure  acid  remains  colorless,  and 
traces  of  hippuric  acid  give  a  brown  to  black  color. — For  am- 
monium or  other  nitrogenous  compounds  accompanying  an  acid 
made  from  the  urine,  dissolve  in  a  wide  test-tube  with  a  little 
alcohol  and  fixed  alkali  to  strong  alkaline  reaction,  heating  to 
near  boiling,  and  testing  the  vapor  with  moistened  red  litmus-pa- 
per and  by  the  odor,  for  ammonia. — For  chlorides  and  sulphates, 

1  Hager  severely  criticises  the  Ph.  Germ,  direction  to  give  8  hours  for  this 
reaction.  Upon  this  and  other  tests  of  genuineness  of  natural  benzoic  acid,  see 
LENKEN,  1882;  SCHAER,  1882;  SCHNEIDER,  1882;  SCHICKUM,  1882;  SCHACHT,  1881; 
JACOBSEN,  1881 ;  DYMOND,  1883. 


CINNAMIC  ACID.  69 

test  the  saturated  aqueous  solution  with  silver  nitrate  solution, 
and  barium  chloride  solution.  For  chloro-toluenes,  slowly  heat  a 
portion  under  solid  potassium  or  sodium  hydrate  (free  from 
chloride)  on  platinum  foil,  dissolve  the  mass  in  water,  filter  if 
necessary,  acidulate  with  nitric  acid,  and  test  with  silver  nitrate 
solution.  Or  apply  the-  blow-pipe  test  for  chlorine,  with  the 
copper  bead,  as  directed  by  the  U.  S.  Ph. — For  hippuric  acid, 
•  and  gross  organic  and  inorganic  adulterations,  heat  a  portion  to 
vaporization  and  combustion,  on  platinum  foil  or  clean  porcelain. 
It  should  vaporize  and  burn,  with  only  a  residual  stain  :  a  coaly 
mass  or  incombustible  residue  indicating  gross  impurity. — Also, 
apply  any  of  the  solvents  of  benzoic  acid,  chloroform,  ether, 
benzol,  or  carbon  disulphide.  Hippuric  acid  is  but  slightly  solu- 
ble in  ether  or  chloroform. — For  hydrocyanic  acid,  distil  a  por- 
tion with  a  little  water,  and  test  the  distillate  for  conversion  into 
sulphocyanate.  If  a  benzoate  be  tested,  acidulate  with  sulphuric 
acid  before  distilling. 

The  medicinal  benzoates  (see  <?,  p.  62)  are  especially  liable 
to  be  found  with  the  injurious  impurities  of  artificial  benzoic 
acid.  They  should  be  tested,  as  above  indicated,  for  cyanides, 
chlorinated  compounds,  salts  of  hippuric  acid,  etc. 

CINNAMIC  ACID.  Zimmtssaure.  Cinnamylsaure.  Acide 
Cinnamique.  C9H8O3=:14:8  (monobasic).-  Phenyl-acrylic  acid: 
C6H5.CH.CH.CO2H. — Sources:  As  free  acid  or  in  combin- 
ation with  ethereal  bases,  in  various  balsams  and  with  resins. 
Balsam  of  Peru  contains  often  10  per  cent,  of  the  acid  free, 
and  a  larger  quantity  as  cinnamate  of  benzyl  (C7EL) ;  tolu  bal- 
sam, 10  or  12  per  cent,  of  cinnamic  acid,  mostly  free  ;  storax, 
a  variable  quantity  of  the  acid,  mostly  in  combination;  and 
some  varieties  of  benzoin  contain  it.  It  is  found  in  large 
crystals  in  old  oil  of  cinnamon,  formed  by  atmospheric  oxida- 
tion of  cinnamic  aldehyde,  (C6H5.CH.CH.COH)  the  cinnamon 
oil  itself.  The  leaden  packages  in  which  oil  of  cinnamon  is  im- 
ported sometimes  furnish  a  deposit  of  lead  cinnamate  with  free 
cinnamic  acid.  It  is  producible  from  benzoic  aldehyde.  Fur- 
ther, see  g. 

Cinnamic  acid  is  characterized  by  its  crystalline  form  in  a 
sublimate  (a)  and  its  precipitation  as  free  acid  (c).  It  is  revealed, 
when  only  in  traces,  by  its  oxidation  to  benzaldehyde  (d),  a  dis- 
tinction from  benzoic  acid.  Its  metallic  precipitates  are  not  mark- 
edly characteristic,  that  with  iron  resembling  "Benzoate  (d).  It  is 
separated  by  methods  used  for  benzoic  acid,  and  from  the  latter 
with  some  difficulty  (e).  Estimated  gravimetrically  as  free  acid 


70  CINNAMIC  ACID. 

(/*).     Its  natural  combinations,  and  sources  of  production,  are 
described  in  g. 

a. — Cinnamic  acid  is  a  colorless  solid,  crystallizing  (from 
vapor  or  solution)  in  monoclinic  prisms  or  plates.  Specific  gra- 
vity (at  mean  temperature,  water  at  4°  C.  as  1.)  1.247  (SCHRCEDER, 
1879).  It  melts  at  133°  C.  (271.4°  F.)  (MILLER,  1877  ;  TIEMANN 
and  HERZFELD,  1877).  It  boils  at  300°  to  304°  C.  (572°-5790  F.) 
(E.  KOPP,  1849),  suffering  partial  decomposition  unless  heated 
gradually,  the  products  containing  cinnamene  (C81I8),  stilbene, 
carbon  dioxide,  etc.  It  vaporizes  much  below  its  boiling  point. 

5. — Without  odor,  and  of  an  aromatic,  slightly  sharp  taste. 
The  vapors  are  pungent  and  excite  coughing. — In  doses  of  5  to 
6  grams  (80  to  90  grains)  it  causes  a  just  perceptible  irritation  of 
the  throat.  After  its  administration  the  urine  contains  cinnamic 
acid  with  hippuric  acid,  the  latter  probably  preceded  by  oxida- 
tion to  benzoic  acid  (ERDMANN  and  MARCH  AND,  1842). 

G. — Yery  sparingly  soluble  in  cold  water,  moderately  soluble 
in  boiling  water,  freely  soluble  in  alcohol,  soluble  in  ether.  With 
litmus  and  other  indicators  it  shows  an  acid  reaction.  The  me- 
tallic cinnamates  are  monobasic,  stable  salts.  Those  of  the  alkali 
metals  are  soluble  in  water ;  of  alkaline-earth  metals  more  soluble 
in  hot  water  ;  most  others  little  soluble  in  water.  Aqueous  solu- 
tions of  alkali  cinnamates,  on  adding  an  acid,  give  a  precipitate  of 
cinnamic  acid.  By  dry  distillation  they  yield,  among  other  pro- 
ducts, benzaldehyde.  Ethyl  cinnamate  boils  at  266°  C.,  is  of 
specific  gravity  1.3,  nearly  insoluble  in  water,  soluble  in  alcohol 
and  in  ether.  Methyl  cinnamate  has  a  specific  gravity  of  1.106, 
boils  at  241°  C.,  and  is  insoluble  in  water.  KRAUT  and  MERLING 
(1881)  mention  a  compound  of  cinnamic  acid  with  hydrochloric 
acid. 

d. — Oxidized  with  permanganate  of  potassium,  or  with 
dichromate  of  potassium  and  sulphuric  acid,  cinnamic  acid  yields 
benzaldehyde,  or  bitter-almond  oil,  recognized  by  its  odor.  The 
solid  material  may  be  treated  with  half  as  much  solid  perman- 
ganate, rubbing  with  a  little  water  in  a  mortar.  Or  the  solu- 
tion may  be  charged  with  permanganate  solution,  and  warmed. 
C6H5.CH.CH.C02H+40=C6II5.CqH  +  2C02+H20.  The 
oxidation  may  continue  to  the  conversion  of  the  benzaldehyde 
into  benzoic  acid. — Ferric  salts  with  solutions  of  cinnamates 
give  a  yellow  precipitate  of  ferric  cinnamate  ;  manganous  salts 
with  excess  of  cinnamates,  a  white  precipitate  (none  with  ben- 
zoates) ;  lead  acetate,  a  precipitate  of  lead  cinnamate ;  and  silver 


BERBERINE.  71 

nitrate,  a  stable  white  precipitate  of  normal  silver  cinnamate. 
The  barium  and  calcium  precipitates  dissolve  in  hot  water. 

e. — Aqueous  solutions  of  free  cinnamic  acid  can  be  concen- 
trated, and  the  residue  can  be  dried  on  the  water-bath,  without 
loss  of  more  than  traces  of  the  acid.  Sublimation  cannot  be  em- 
ployed, under  ordinary  conditions,  without  waste  by  decomposi- 
tion. Precipitation  of  cinnamic  acid,  in  cold  and  not  dilute 
solutions  of  cinnamates,  by  adding  hydrochloric  acid,  serves  well 
for  separation.  The  free  acid  may  be  dissolved  from  aqueous 
or  dry  mixtures  by  repeated  portions  of  ether. — Benzoic  and 
salicylic  acids  are  liable,  if  present,  to  appear  in  separates  with 
cinnamic  acid.  Among  solid  sublimable  acids  may  be  further 
named  succinic  and  gallic  acids,  but  these  are  soluble  in  water. 
As  to  separation  of  cinnamic  from  benzoic  acid,  see  the  latter 
(e,  7,  etc.) 

f. — Cinnamic  acid  may  be  weighed,  as  C9H8O2.  For  this 
purpose  it  may  be  prepared  in  crystals  from  alcohol  or  hot  water, 
or  in  residue  from  ether,  or  in  precipitate  from  cold  concentrated 
solution. 

g. — The  appearance  of  cinnamic  acid  in  analysis  raises  the 
question  of  its  production,  or  liberation,  by  the  operations  of  the 
analysis,  from  an  ethereal  salt  of  cinnamic  acid,  or  from  its  alde- 
hyde, or  alcohol.  Cinnamein,  benzyl  cinnamate,  making  a  large 
part  of  Peru  balsam  and  a  small  part  of  tolu  balsam,  is  liquid  at 
ordinary  temperature,  neutral  in  reaction,  of  sp.  gr.  1.098  at 
14°  C.,  boiling  with  some  decomposition  at  340°-350°  C.,  not 
soluble  in  water,  soluble  in  alcohol,  ether,  or  carbon  disulphide. 
Styracin,  cinnamyl  cinnamate,  is  fonhd  in  storax,  crystallizing  in 
needles  or  four-sided  prisms,  of  sp.  gr.  1.085  at  16°  C.,  melting 
at  38°  to  44°  C.,  and  distilling  with  steam  at  180°  C.  without  de- 
composition. It  is  insoluble  in  water,  soluble  in  hot  alcohol 
and  in  ether.  Both  cinnamein  and  styracin  are  easily  saponified 
by  digestion  with  fixed  alkali  or  alkali  carbonate,  when  the 
aqueous  solution,  by  acidulation  with  hydrochloric  acid,  yields 
cinnamic  acid.  The  styrone  of  storax  and  Peru  balsam  is  cin- 
namic alcohol  (C6H5 .  CH .  CH .  COH3) ;  and  the  cinnamene  or 
styrol,  of  storax,  is  the  related  hydrocarbon,  C6H5 .  CH .  CH2.  The 
union  of  benzoic  acid  with  cinnamic  acid,  (C7H6O2)2C9H8O2, 
melts  at  95°  C. 

BENZOYL-ECGONINE.     See  COCA  ALKALOIDS. 
BERBERINE.    C20H17lSrO4=335.— The  yellow  alkaloid  of 


72  BERBERINE. 

Hydrastis  canadensis,  species  of  Berberis  and  Coptis,  and  other 
plants.  As  a  hydrochloride,  often  commercially  named  hy- 
drastine.1 

Found  as  follows  : 
In  Hydrastis   canadensis,  Ranunculacese,  1.3   to  1.8  per  cent. 

(LLOYD). 

"  Coptis  trifoliata,  4$  (Perrins). 
"        "      teeta  (India),  8.5$  (PERKINS). 
"  Xanthoriza  apifolia. 
"  Berberis  vulgaris,  Berberidacese,  12$  (Perrins). 

aquifolium. 
"        "        anstata. 
"  Jeifersonia  dipliylla. 

"  Caulophylum  thalictroides  (Husemann's  Pfl.) 
"  Jateorrhiza  calumba  (calumba  root),  Menispermacese. 
"  Minispermurn  canadense. 

"  Coscinium  fenestratum  (Ceylon  calumba  wood). 
"  Coelocline  polycarpa,  Anonacese. 
"  Xanthoxylum  clava  Herculis,  E-utacese. 

In  several  of  these  sources  berberine  is  accompanied  with  a 
colorless  alkaloid.  Its  chemical  relation  to  hydrastine  is  men- 
tioned in  the  description  of  the  latter. 

Berberine  responds  to  tjie  general  tests  for  alkaloids  (<#), 
among  which  it  is  at  once  distinguished  by  its  color  and  by  the 
crystalline  precipitations  of  its  hydrochloride  and  nitrate  (d). 
These  precipitations,  as  well  as  its  abundant  solubility  as  a  free 
alkaloid  in  hot  water,  serve  to  separate  it  from  other  alkaloids. 
Its  separation  from  its  vegetable  sources  is  outlined,  with  refe- 
rences, under  e.  It  is  estimated  as  free  alkaloid  or  crystalline 
salt,  gravimetrically ;  by  Mayer's  solution,  volumetrically. 

d. — In  brown-red  pencils,  grouped  in  irregularly  radiate  clus- 
ters ;  also  in  branched,  curved,  and  pointed  prolongations ;  some- 
times appearing  orange-red  to  yellow.  In  amorphous  and  ob- 

1  As  first  found  in  different  plants,  this  alkaloid  was  named  as  follows: 
In  Geffraya  inermis,  bark,  by  Huttenschmid,         in  1824,  as  jamaicine. 
"  Xanthoxylum  clava  H.,  by  Chevallier  and  P.,  in  1826,  as  xanthopicrite. 
"  Hydrastis  canadensis,      by  Rafinesque,  in  1828,  as  hydrastine. 

"  Berberis  vulgaris,  by  Buchner  and  H.,     in  1830,  as  berberine. 

"  We  .  .  .  think  it  unfortunate  that,  since  the  name  Hydrastis  was  ac- 
cepted by  botanists,  it  was  not  followed  by  chemists  in  the  naming  of  its  pro- 
minent constituent,  the  yellow  alkaloid  ":  J.  U.  and  C.  Gr.  LLOYD,  in  "  Drugs 
and  Medicines  of  North  America,"  1884,  p.  98. — An  early  paper  on  this  alkaloid 
was  that  of  J.  D.  PERRINS,  1862:  Jour.  Chem.  8oc.,  15,  339. 


BERBERINE.  73 

scurely  crystalline  forms  it  is  yellow.  At  120°  C.  it  melts  to  a 
red-brown  resinous  mass.  As  crystallized  from  water,  it  loses 
19.26$  water  at  about  100°  C.  (FLEITMANN),  indicating  about 
5H2O  of  crystal- water  in  air-dry  crystals. — The  hydrochloride, 
C20H-L7NO4HC1.2H2O,  forms  large,  lustrous,  golden-yellow  crys- 
tals, in  pencils,  with  ends  both  square  and  oblique,  slightly 
grouped. — The  hydrobromide,  normal  with  1^H2O,  forms  bright 
yellow,  fine  needles. — The  hydriodide,  normal,  forms  reddish- 
yellow  needles. — The  nitrate  is  a  normal  salt,  in  clear  yellow 
needles. — Berberine  sulphate,  (C20H17E"O4)2II2SO4,  crystallizes 
in  irregular  oblong  plates  of  garnet-red  color,  or  in  stellate 
spangles  of  lemon-yellow  to  orange-yellow  color. — Berberine 
acid  phosphate,  C20H17KO4(H3PO4)7,1  is  a  canary-yellow  powder. 

5. — Berberine  and  its  salts  are  inodorous  and  of  a  bitter 
taste.  It  is  given,  medicinally,  in  doses  of  2  to  5  grains ;  60 
grains  having  been  taken  without  injury.  Small  animals  are 
poisoned  by  it;  1  gram  subcutaneously  causing  the  death  of 
dogs  in  8  to  40  hours. 

c. — The  free  alkaloid  is  soluble  in  about  500  parts  of  cold 
water,  freely  soluble  in  boiling  water;  sparingly  soluble  in  cold, 
freely  soluble  in  hot,  alcohol ;  insoluble  in  ether  or  in  petroleum 
benzin  ;  slightly  soluble  in  chloroform  or  in  benzene. — Its  solu- 
tions have  a  neutral  reaction.  In  salts  or  from  acidulated  solu- 
tions it  is  imperfectly  taken  up  by  benzene,  chloroform,  or  amyl 
alcohol,  not  by  petroleum  benzin. — It  is  permanent  in  the  air 
and  in  solutions. — The  solubilities  of  salts  of  berberine  are  in- 
dicated under  d. 

d. — The  caustic  alkalies  color  berberine  brown,  with  forma- 
tion of  a  resinous  mass  on  boiling.  On  acidulating  an  aqueous 
solution  of  berberine  with  hydrochloric  or  nitric  acid  the  salt 
of  the  alkaloid  quickly  crystallizes  in  bright-colored  crystals, 
mostly  golden  yellow,  thrown  out  of  solution  more  perfectly  by 
adding  a  considerable  excess  of  the  acid.  The  hydrochlorate 
is  soluble  in  about  500  parts  of  water  or  250  parts  of  alcohol 
(from  data  of  LLOYD)  ;  the  nitrate  is  very  slightly  soluble  in 
dilute  nitric  acid  (PERKINS)  ;  the  normal  sulphate,  in  10  parts 
of  water  or  293  parts  of  alcohol  (LLOYD)  ;  the  super  acid  phos- 
phate, in  10  parts  of  water. 

The  general  reagents  for  alkaloids  give  precipitates  of  ber- 
berine, mostly  yellow — the  phosphomolybdate  turning  blue  on 

1  PARSONS  and  WRAMPELMEIER,  1877;  COBLENTZ,  1884. 


74  BERBERINE. 

adding  ammonia.  The  red-brown  precipitate  by  iodine  in  po- 
tassium iodide  solution,  when  crystallized  from  hot  alcohol,  ap- 
pears in  green,  iridescent  scales.— Concentrated  sulphuric  acid 
gives  a  brown  to  orange  color ;  turning  black  to  violet  by  add- 
ing dichromate,  as  in  the  fading-purple  test  for  strychnine. 
Froehde's  reagent  gives  a  green  to  brown  color.  Chlorine 
•water  added  to  an  aqueous  acidulous  solution  of  the  hydro- 
chloride  gives  a  band  of  bright-red  color  at  the  point  of  contact, 
visible  as  a  rose  tint  in  a  dilution  to  250000  parts  (KLTJGE, 
1875). — By  distillation  with  milk  of  lime,  or  with  lead  dioxide, 
quinoline  is  obtained. 

e. — Berberine  is  separated  from  Hydrastis  canadensis  (or 
other  plant  containing  it),  according  to  PEKRINS  (1862),  by  treat- 
ing with  boiling  water  to  prepare  a  concentrated  extract,  extract- 
ing this  with  alcohol,  adding  a  little  water  and  distilling  off  the 
alcohol,  then  adding  dilute  nitric  acid  (Perrins)  or  hydrochloric 
acid  in  some  excess,  and  leaving  several  days  for  the  crystalliza- 
tion of  the  salt.  To  obtain  the  free  berberine,  add  calcium  hy- 
drate or  barium  carbonate,  extract  with  hot  alcohol,  and,  after 
evaporating  off  the  alcohol,  crystallize  from  a  hot  watery  solu- 
tion, drying  the  crystals  at  a  temperature  not  above  25°  C.  For 
the  preparation  of  the  various  salts  of  berberine,  as  well  as  its 
recovery  from  the  vegetable  drugs  containing  it,  see  Lloyd's 
"  Drugs  of  North  America,"  I,  98. 

From  most  alkaloids  berberine  is  separated  (1)  by  its  greater 
solubility  as  free  alkaloid  in  hot  water ;  (2)  by  its  much  smaller 
solubility  as  hydrochloride  in  dilute  hydrochloric  acid.  As  to  se- 
parations by  the  solvents  immiscible  with  water,  see  (c),  p.  73. 

f — Quantitative. — Berberine  may  be  weighed  as  free  alka- 
loid, anhydrous,  by  drying  at  100°-liO°  C.  The  nitrate,  normal, 
anhydrous,  may  be  dried  at  100°  C.  for  weighing  (PERKINS). 
The  precipitate  by  potassium  mercuric  iodide,  washed  and 
dried  at  100°  C.,  contains  very  nearly  50  per  cent,  of  anhy- 
drous berberine  (BEACH,  and  the  author,  1876),  corresponding 
nearly  to  the  composition  (C20H17NO4)2(HI)2HgI2  (48.55$).  In 
the  volumetric  method  by  Mayer's  solution  Beach  found  the  val- 
ue of  a  c.c.  of  the  solution  to  be  0.0425  gram  of  the  anhydrous 
alkaloid.  In  results  reported  by  the  author  in  1880  '  the  washed 
iodomercurate  was  found  to  contain  a  mean  of  52  10#  of  the  al- 
kaloid. Perrins  weighed  the  washed  and  dried  precipitate  of 
platinic  chloride  (C20H17NO4)2(HCl)2PtCl4. 

^'Estimation  of  Alkaloids  by  Potassium  Mercuric  Iodide,"  Am.  Chem. 
Jour.,  2,  303. 


BUTYRIC  ACID.  75 

BRUCINE.     See  STKYCHNOS  ALKALOIDS. 
BUTTER.     See  FATS  and  OILS. 

BUTYRIC  ACID.  C4H8O2=88  (monobasic).  Normal  bu- 
tyric acid,  or  propyl-carboxyl,  CHgCIIgCHg.COgH.1— -The  bu- 
tyric acid  of  glycerides  of  milk  fat,  and  of  the  butyrous  fermen- 
tation, following  the  lactous  fermentation,  of  sugar.  Found 
among  the  fat  acids  of  cod-liver  oil. 

Normal  butyric  acid  is  characterized  by  its  odor  when  free 
and  by  the  very  different  odor  of  its  ethyl  ester  (d).  It  is  sepa- 
rated by  distillation,  by  solution  in  ether,  and  by  the  solubility 
of  its  calcium  salt  in  alcohol  (e).  It  is  estimated  by  the  acidi- 
metry  of  the  free  acid  (f).  Further,  see  under  Butter  Fats, 
Index. 

a. — Normal  butyric  acid  is  a  colorless,  limpid  liquid,  solidify- 
ing in  tabular  forms  at  — 19°  C.,  having  a  specific  gravity  of  0.958 
atl4°C.,  boiling  at  162.3°  C.,  distilling  completely  by  itself, 
better  with  water,  and  vaporizing  at  common  temperature.  Its 
oil-spot  on  paper  is  not  permanent. 

The  butyrates  are  crystallizable,  in  tabular  or  needle-shaped 
forms,  usually  with  fat-lustrous  surfaces.  When  quickly  heated 
they  carbonize  abundantly ;  when  slowly  heated  they  evolve 
rancid-smelling  vapors  and  carbonize  slightly. 

b. — The  odor  of  pure  normal  butyric  acid  somewhat  resem- 
bles rancid  butter,  but  is  less  disagreeable  and  more  pungent, 
approaching  to  the  acetous  odor.  The  taste  is  acidulous  and 
biting,  and  unless  diluted  it  is  somewhat .  caustic  to  the  tongue 
and  irritating  to  the  skin.  Its  glyceride,  conjugated  with  gly- 
cerides of  non  volatile  fat  acids,  is  a  food  constituent  especially 
provided  for  the  young  in  the  order  of  nature.  Ethyl  butyrate 
has  a  fragrant  odor  of  the  pineapple,  in  which  it  is  found. 

c. — Solubilities. — Normal  butyric  acid  is  freely  soluble  in 
water,  though  but  little  soluble  in  aqueous  solutions  of  sodium 
chloride  and  various  other  salts.  It  is  freely  soluble  in  alcohol 
and  in  ether.  The  solutions  redden  litmus,  and  decolor  alkaline 
phenol- phthalein  solution.  The  metallic  butyrates,  for  the  most 
part,  save  those  of  silver  and  lead,  are  soluble  in  water,  and  some 

1  There  are  two  butyric  acids,  as  four-carbon  members  of  the  fatty  acid 
series,  CnH2n02.  The  other  one  is  Isobutyric  acid  (CH^CH.COaH.  or  di- 
methyl acetic  acid.  Isobutyric  acid  is  found  among  the  fat  acids  of  castor 
oil. 


76  BUTYRIC  ACID.  . 

of  them  dissolve  in  alcohol.  Alkali  butyrates  are  neutral  to 
litmus.  Ethyl  butyrate  is  sparingly  soluble  in  water,  soluble  in 
alcohol  in  all  proportions. 

d. — Normal  butyric  acid  is  identified  by  its  pungent,  rancid 
odor  when  free  (5),  and  the  pineapple  odor  of  its  ethyl  ester, 
while  its  glyceride  and  its  alkali  salts  are  nearly  odorless. 
Warming  butyric  acid  or  a  metallic  butyrate  with  a  little  alco- 
hol and  about  twice  as  much  undiluted  sulphuric  acid,  the  ethyl 
butyrate  is  readily  formed,  and  odor  obtained.  If  the  butyric 
acid  is  free,  in  dilute  solution,  it  should  be  neutralized  with 
alkali  and  the  solution  concentrated  for  the  test.  Ethyl  butyrate 
is  stable,  not  readily  saponified.  Glyceride  of  butyric  acid, 
butyrin,  should  be  saponified  by  alcoholic  potash  before  applying 
the  test. — Calcium  or  barium  chloride  does  not  precipitate  mode- 
rately dilute  solutions  of  butyric  acid  or  its  salts.  Silver  nitrate 
gives  a  precipitate  in  moderately  concentrated  solutions.  Lead 
acetate  and  subacetate,  in  moderately  concentrated  solutions, 
give  precipitates  which  dissolve  in  alcohol  or  hot  water,  and  melt 
on  heating.  Ferric  chloride,  in  solutions  of  butyrates,  gives  a 
brownish-yellow  precipitate,  as  formed  in  dilute  solutions  much 
resembling  the  benzoate,  and  not  formed  by  free  butyric  acid 
except  in  concentrated  solutions. 

e. — Separation. — Normal  butyric  acid,  in  alkali  salt  solutions, 
can  be  concentrated  on  the  water-bath  without  loss.  By  treating 
metallic  butyrates  with  phosphoric  acid  or  dilute  sulphuric  acid, 
and  distilling  persistently,  all  the  butyric  acid  can  be  obtained. 

Butyric  acid  is  separated  from  acetic  and  other  homologous 
acids  by  the  greater  solubility  of  barium  butyrate  in  alcohol : 
The  free  acids  are  saturated  with  barium  hydrate  solution,  the 
mixture  concentrated  enough  to  stiffen  when  cold,  then  treated 
with  about  ten  parts  of  strong  alcohol,  set  aside  one  or  two 
hours,  and  filtered,  washing  with  alcohol.  The  residue  will 
contain  the  most  of  the  acetate,  while  the  butyrate  will  mainly 
be  in  the  solution.  Of  absolute  alcohol,  1000  parts  dissolve 
11.72  parts  of  barium  butyrate,  0.28  parts  of  barium  acetate, 
0.05  parts  barium  formate,  and  2.61  parts  of  barium  propidnate 
(LucKE,  1872). 

Butyric  acid  may  be  recovered  from  aqueous  mixtures,  as  a 
free  acid,  by  saturating  with  sodium  chloride  or  with  calcium 
chloride,  and  shaking  with  ether.  From  the  ethereal  solution  it 
is  recovered,  as  alkali,  salt,  by  shaking  with  a  slight  excess  of 
fixed  alkali  solution,  or  as  free  butyric  acid,  with  only  slight 
waste,  by  the  spontaneous  evaporation  of  the  ether. 


CAFFEINE. 


77 


f.  —  Quantitative.  —  Butyric  acid  is  estimated  with  ease,  volu- 
metrically,  by  standard  solutions  of  alkali,  fixing  the  neutral 
point  either  with  litmus-papers  or,  more  exactly,  with  phenol- 
phthalein.  Each  c.c.  of  normal  alkali  saturates  0.088  gram,  and 
each  c.c.  of  decinormal  alkali  saturates  0.0088  gram,  of  absolute 
butyric  acid.  Of  a  mixture  containing  no  other  acid,  if  4.4 
grams  be  taken,  c.c.  of  N"  alkali  X  2  =  per  cent,  of  free  butyric 
acid,  or  c.c.  of  yV  alkali  X  20  =  per  cent,  of  free  butyric  acid. 

CAFFEINE.  Theine.  Guaranine.  Coffein  or  Koffein. 
•Oaf  eine  (French).  Methyl-theobromine.  C8H10N4O2=194.  ' 
(Crystallizes  with  1  aq.  ;  also,  anhydrous.)  —  A  trimethyl  xan- 
thine  :  C5II(CII3)3N4Q2  ;  2  xanthine  being  producible  from  gua- 
nine,  or  uric  acid. 

In  Tea          (prepared  leaf  of  Camellia  Thea),  2  to  3  per  cent. 

"  Coffee      (dried  seed  of  Coffea  arabica),        1  per  cent. 

"  Guarana  (crushed  seed  of  Paulinia  sorbilis),  4  per  cent. 

"  Mate        (leaf  of  Ilex  paraguayensis),  1J  per  cent. 

"  Cola  nut  (seed  of  Sterculia  acuminata),        2  per  cent. 
These  percentages  are  given  to  represent  average  yields.3 

Caffeine  is  producible  from  theobromine  and  from  xanthine 
(STRECKER,  FISCHER) 

Caffeine  is  identified  by  the  murexoin  test  (d),  and  the  form 
in  which  it  crystallizes  under  the  microscope  (a).  It  shares  its 
most  distinctive  tests  with  Theobromine,  from  which  it  differs 
greatly  in  solubilities.  It  is  distinguished  from  most  other  alJca- 
Xoids\yj  non-precipitation  with  potassium  mercuric  iodide,  by  yield- 
ing cyanide  when  smelted  with  soda-lime  (d),  and  by  dissolving  in 
water,  and  from  acidulous  mixture  dissolving  in  chloroform,  etc. 
{c  and  e).  It  is  separated  as  stated  under  e,  and  estimated  in 
tea,  coffee,  guarana,  etc.,  by  its  weight,  as  obtained  (1)  by  extract- 
ing with  water  and  dissolving  the  residue  in  ether,  (2)  by  ex- 
tracting with  water  (and  alcohol)  and  shaking  out  with  chloro- 
form, (3)  by  extracting  with  chloroform  and  dissolving  the 
residue  in  water,  (4)  by  sublimation  (/).  Tests  for  impuri- 
ties, g. 


LIEBIG,  1832  :  Ann.  Chem.  Phar.,  I,  17. 

STRECKER,  1861  :  Ann  Chem.  Phar.,  118,  72,  151.  E.  FISCHER,  1882: 
Ann.  Chem.  Phar.,  215,  253-320:  Jour.  Chem.  Soc.,  1883,  Abs  ,  354.  E. 
SCHMIDT.  1883. 

3  For  tea  and  coffee  and  guarana,  DRAGENDORFF,  1874  :  "  Werthbestim- 
mung."  56  .  SQUIBB,  1884  :  fiphemeris,  606,  614,  6.16.  For  Paraguay  tea,  BY- 
ASSON,  1878.  For  Cola  nut,  HECKEL  and  SCHLAGDENHAUFFEN,  1884  :  Phar. 
Jour.  Trans.,  Am.  Jour.  Phar.  Also,  ATTFIELD,  1865.  E.  SCHMIDT 
And  report  of  J.  F.  GEISLER  in  article  "  TEAS  "  in  this  work. 


78  CAFFEINE. 

a. — Caffeine  appears  in  long,  slender,  flexible  white  crystals, 
of  silky  lustre,  forming  light,  fleecy  masses.  The  crystals  have 
a  specific  gravity  of  1.23  at  19°  C.  They  are  permanent  in  the 
air.  On  the  spontaneous  evaporation  of  a  drop  or  two  of  an 
aqueous  or  chloroformic  solution,  dilute  enough  to  crystallize 
slowly,  on  a  glass  slide,  characteristic  crystals  are  identified  by  a 
magnifying  power  of  100  to  300  diameters.  The  forms  are 
chiefly  acicular;  finely  pointed  needles  of  some  thickness  at 
their  overlapping  basal  ends  making  irregularly  stellate  groups, 
with  a  few  separate  needles.  Among  these,  of  later  appearance 
and  requiring  the  higher  power  above  named,  are  the  more 
characteristic  forms,  namely :  six-sided  crystals,  dihexagonal 
pyramids  and  prisms,  with  a  few  rhombohedrons.  From  the 
chloroformic  solution  the  stellate  groups  are  found  each  with  a 
single  hexagonal  crystal  in  its  centre. 

Anhydrous  crystals  are  said  to  be  obtained  from  ether  or 
absolute  alcohol.  DRAGENDOKFF  *  directs  to  dry  at  100°  C.  for  a 
constant  weight  of  anhydrous  alkaloid  ;  COMMAILE  (1875)  gives 
the  same  direction.  BLYTH  (1878)  states  that  at  79J°  C.  minute 
microscopic  crystals  in  sublimate  can  be  obtained,  and  a  com- 
plete sublimation  in  long,  silky  crystals  readily  obtained  near 
120°  C. ;  also  that  the  high  subliming  points  given  by  Pelouze 
and  Mulder  must  have  been  given  from  faulty  methods.  When 
anhydrous,  caffeine  melts  at  234°  C.  (STRECKER,  1861),  and  the 
melted  mass  boils  at  384°  C.  with  partial  decomposition,  leaving 
no  residuum. 

1}. — Caffeine  is  without  odor  and  with  a  bitter  taste.  The 
maximum  medicinal  dose  is  about  3  grains :  Br.  Phar.  dose  1  to 
5  grains ;  Ph.  Germ,  maximum  single  dose  3  grains.* 

c. — Caffeine  is  sparingly  soluble  in  cold  water;  freely  soluble 
in  hot  water  and  in  chloroform ;  moderately  soluble  in  alcohol 
and  in  benzene ;  slightly  soluble  in  ether ;  nearly  insoluble  in 
petroleum  benzin  or  carbon  disulphide.  Combination  with  acids 
scarcely  hinders  its  solubility  in  chloroform  or  benzene.  More 
particularly,  the  hydrated  crystals  dissolve  in  68  parts  of  water 
at  15°  to  17°  C.  (CoMMAiLE3) ;  in  75  parts  water  at  15°  C.  (U.  S. 
Ph.) ;  in  80  parts  cold  water  (Ph.  Germ.,  Br.  Ph.) ;  in  9.5  parts 
of  boiling  water  (U.  S.  Ph.) ;  10  parts  boiling  water  (Hager's 

1 "  Werthbestimmung,"  1874,  p.  57. 

2  For  physiological  assays  of  tea,  coffee,  and  guarana,  in  comparison  with 
caffeine,  SQUIBB,  1884  :  Ephemeris,  2,  603,  610,  615,  617. 

3 1875:  Compt.  rend.,  81,  817;  Jour.  Chem.  Soc.,  1876,  i.  779. 


OF  THE 

UNIVERSITY 


ABvxfMx 

CAFFEINE.  79 

Com  men  tar)  ;  2.01  parts  water  at  65°  C.  (COMMAILE).  In  alcohol 
of  about  90  per  cent.,  35  parts  at  15°  C.  (U.  S.  Ph.),  50  parts 
(Ph.  Germ.),  40  parts  at  15°  to  17°  (COMMAILE)  ;  in  absolute  al- 
cohol it  is  less  soluble,  in  155  parts  (Hager's  Commentar).  In 
ordinary  ether  it  dissolves  in  476  parts  at  15°  to  17°  C.  (COM- 
MAILE), 600  parts  (HAGEK).  The  anhydrous  alkaloid  dissolves  in 
75  parts  water  at  15°  to  17°  C.  (COMMAILE)  ;  in  165  parts  absolute 
alcohol  at  15°  to  17°  C.  (COMMAILE)  ;  in  32  parts  boiling  absolute 
alcohol  (COMMAILE)  ;  in  8  parts  chloroform  at  15°  to  17°  C.,  or 
5J  parts  boiling  chloroform  (COMMAILE)  ;  in  2288  parts  of  anhy- 
drous ether  at  15°  to  17°  C.  (COMMAILE);  in  4000  parts  of  petroleum 
benzin  at  15°  to  17°  C.  (COMMAILE). 

Caffeine  is  neutral  to  test-papers,  notwithstanding  its  solu- 
bility in  water.  It  is  a  very  feeble  base.  Salts  of  caffeine  are 
formed  only  by  action  of  concentrated  acids  upon  the  alkaloid  ; 
they  are  all  decomposed  by  water,  alcohol,  and  ether,  and  those 
of  volatile  acids  are  decomposed  by  exposure  to  the  air  (E. 
SCHMIDT)/  Many  of  the  salts  crystallize  in  needles,  the  hydro- 
chloride,  C8H10N4O2  .  HC1,  in  monoclinic  forms.  The  caffeate 
crystallizes  as  C8H10N4O2.C8H8O4.2H2O.  The  sulphate  has 
been  obtained,  from  hot  alcoholic  solution,  in  crystals  of  the 
composition  C8H10N4O2  .  H2SO4  (SCHMIDT).  The  citrate  was  re- 
ported by  LLOYD  (1881)  as  a  possible  definite  salt,  but  so  frail 
that  it  is  decomposed  by  solvents  which  dissolve  citric  acid 
readily  and  caffeine  sparingly  :  it  is  given  by  the  Br.  Ph.  with 
the  formula  C8H10N4O2  .  H3C6H5O7  (implying  that  caffeine  is 
here  a  tri-acid  base).  The  double  salts  of  caffeine  are  less  in- 
stable  (see  dj  platinum,  etc.) 

d.  —  Caffeine  responds  promptly  to  "the  murexid  test"  as 
follows  :  A  portion  of  solid  material  or  a  residue  by  evaporating 
a  liquid  to  be  tested,  not  over  a  grain  or  two  at  most,  is  taken  in 
a  white  porcelain  evaporating-dish,  heated  on  the  water-bath, 
then  covered  with  from  one  to  five  drops  of  hydrochloric  acid, 
when  at  once  a  minute  fragment  of  potassium  chlorate  is 
added,  the  mixture  evaporated  to  dry  ness  and  well  dried  on  the 
water-bath.  When  cold  the  residue  is  slightly  moistened  with 
ammonia  water  applied  by  the  point  of  a  glass  rod.  In  evi- 
dence of  caffeine  a  purple  color  (that  of  murexoiri)  is  obtained 
after  the  action  of  ammonia  ;  a  reddish-yellow  to  pinkish  color 
before  the  action  of  ammonia.  0.00005  gram  of  caffeine,  in  a 
residue  small  enough  to  be  covered  by  one  drop  of  hydrochloric 
acid,  yields  decisive  evidence  by  this  test.  Fuming  nitric  acid, 

1  1881:  Ber.  d.  chem.  &es.,  14,  814;  Jour.  Chem.  Soc.,  1881,  Abs.,  746. 


8o  CAFFEINE. 

or  chlorine  water,  serves  as  the  oxidizing  agent,  but  less  effi- 
ciently. The  products  of  the  oxidation  include  amalic  acid  and 
hydrocyanic  acid.1  By  the  action  of  ammonia  the  murexoiii  is 
formed.  The  amalic  acid  and  murexoin  are  tetramethylated  de- 
rivatives of  the  corresponding  products  obtained  in  the  murexid 
test  of  uric  acid,  thus : 

By  the  oxidation  By  the  action  of  ammonia, 
(with  other  products). 

Uric  acid:    Alloxantin,  C8H4N407.  Murexid,  NH4.C8H4N506. 

Caffeine:      Amalic  acid,  C8(CH3)4N407.  Murexoin,  NH4 .  C8(CH3)4N506. 

The  murexoin  purple  from  caffeine  is  decolored  and  not 
turned  blue,  by  adding  potassium  hydrate  solution,  a  distinction 
from  the  murexid  purple  from  uric  acid.  The  amalic  acid  stains 
the  skin  red  (also  a  characteristic  of  alloxantin). 

Tannic  acid  precipitates  caifeine  from  aqueous  solutions  not 
very  dilute,  the  precipitate  being  somewhat  soluble  in  excess  of 
the  reagent. — Phosphomolybdate  of  sodium  gives  a  yellowish 
precipitate,  soluble  in  warm  sodium  acetate  solution,  from  which 
free  caifeine  separates  on  cooling  (SONNENSCHEIN)  — Platinum 
chloride  and  hydrochloric  acid  with  concentrated  solution  of 
caifeine  gives  an  orange-colored  precipitate,  dissolving  when 
heated,  crystallizing  on  cooling  (C8II10lSr4O2 .  HC1)2 .  PtCl^,  solu- 
ble in  20  parts  of  water  (STAHLSCHMIDT). — Potassium  bismuth 
iodide  gives  a  precipitate  on  standing,  soluble  in  3000  parts 
water  (THRESH,  1880). — JSTo  precipitates  are  obtained  with  po- 
tassium mercuric  iodide,  or  with  iodine  in  potassium  iodide  solu- 
tion (distinction  of  caifeine,  theobromine,  and  colchicine  from 
nearly  all  other  alkaloids). — On  heating  caifeine  with  solid  po- 
tassium hydrate,  or  boiling  with  strong  solution  of  this  reagent, 
methylamine  is  evolved  and  recognized  by  its  strong,  ammonia- 
like  odor.  Strongly  heating  a  dry  mixture  of  caffeine  and  soda- 
lime,  ammonia  is  evolved,  as.  with  other  alkaloids,  while,  in  dis- 
tinction from  most  other  alkaloids,  a  part  of  the  nitrogen  is  re- 
tained in  cyanogen,  as  alkali  cyanide,  revealed  by  treating  the 
mass  with  water  and  testing  a  filtered  portion  for  cyanides. 

e. — Separations. — Caifeine  can  be  separated  from  the  greater 
number  of  alkaloids  by  its  greater  solubility  in  water,  and  by 
its  being  dissolved  from  acidulous  mixtures  by  chloroform,  ben- 
zene, and  (sparingly)  by  ether.  From  non-volatile  matters  it  is 
separable  by  careful  sublimation  from  a  well-dried,  finely  pow- 
dered mass,  at  100°  to  150°  C.  (BLYTH).  Separations  from  tea, 
coffee,  guarana,  etc.,  are  presented  under  f. 

1  ROCHLEDER,  1849:  Ann.  Chem.  Phar.,  71,  1.    SCHWARZENBACH,  1859. 


CAFFEINE.  .  8 1 

y. —  Quantitative. — The  quantity  of  caffeine  is  determined 
gravimetrically  by  weighing  the  alkaloid.  According  to  BLYTH 
(1878)  dry  caffeine  begins  to  sublime  at  79.5°  C.  (175°  F.),  but 
the  same  author  states  *  that,  so  far  as  decided  by  his  experiments, 
loss  of  the  alkaloid  does  not  occur  at  100°  C.  until  the  material  is 
quite  dry,  and  there  is  no  testimony  to  show  that  loss  occurs 
from  concentrating  limpid  aqueous  solutions  on  the  water-bath. 
At  all  events  this  has  been  done  in  many  assay  methods.  And 
in  nearly  all  methods  except  Blyth's  it  is  directed  to  dry  residues 
or  crystals  of  caffeine  at  100°  C.  for  weight,  an  exposure  to  which 
the  author  just  named  demurs. 

For  estimation  of  the  caffeine  in  tea,  coffee,  guarana,  mate, 
or  cola  several  processes  are  serviceable,  as  follows  : 3  1.  DEAGEN- 
DORFF'S  process  requires  to  exhaust  5  grams  of  the  substance  by 
maceration  with  boiling  water,  evaporating  the  filtrate  with  2 
grams  magnesia  and  5  grams  of  ground  glass.3  The  pulverulent 
residue  is  transferred  to  a  flask,  macerated  with  60  c.c.  of  ether 
for  24  hours,  filtered,  and  the  residue  treated  three  or  four  times 
with  the  same  quantity  of  ether.  The  ether  is  evaporated  and  the 
residue  weighed.  A  smaller  quantity  of  chloroform  may  be  sub- 
stituted, but  does  not  give  as  pure  alkaloid. 

2.  Dr.  SQUIBB  (1884)  takes  10  grams  of  powdered  guarana  and 
2  grams  of  calcined  magnesia,  boiling  with  100  c.c.  of  water  for 
five  minutes,  adding  while  hot  50  c.  c.  of  strong  alcohol,  draining 
on  a  filter,  and  percolating  the  residue  with  a  mixture  of  60  c.c. 
of  water  and  40  c.c.  of  alcohol.  Boil  the  residue  again  with 
100  c.c.  of  this  mixture  of  alcohol  and  water,  and  drain  and  per- 
colate until  exhausted,  or  until  the  total  liquid  amounts  to  300  or 
350  c.c.  Evaporate  this  on  a  water-bath  to  about  20  c.c.,  and 
transfer  to  a  separator,  rinsing  with  a  little  water.  Shake  out 
with  three  or  four  portions  each  of  25  c.c.  of  chloroform.  The 
chloroform  solution  is  evaporated  in  a  tared  beaker  for  weight. 
The  last  chloroform  washing  may  be  evaporated  in  a  separate 

1  "  Foods,"  1882,  p.  330. 

2  DRAGENDORFF,  1874,  1882:  "  Werthbestimmung,"  57;  "  Plant  Analysis," 
London,   1884,  62,  186.     SQUIBB,  1884:  Ephemeris,  2,  606,  614,  616.     BLYTH, 
1877,  1882:   Analyst,  2,   39;  "Foods/'  330.     COMMAILE,  1875:  Compt.  rend., 
81,  817;  Jour.  Uhem.  Soc.,  1876,  i  779. 

3  Those  who  depend  upon  the    "extraction  apparatus"   for  exhausting 
drugs  in  estimation  may  prefer  to  apply  hot  water  to  the  drug  by  continuous 
percolation  in  this  apparatus,  heated  by" a  sand-bath.     Then  the  smaller  quan- 
tity of  solution  can  be  evaporated  in  the  receiver  of  the  apparatus,  after  adding 
the  magnesia  and  sand,  by  aid  of  a  "  filter-pump,"  at  temperature  not  above 
78°  C. ;  and  the  final  residue  by  evaporation  of  the  ether,  dried  below  80°  C. 
-A.  B.  P. 


82  CAFFEINE. 

tared  capsule  for  indication  of  the  completion  of  the  extraction. 
The  caffeine  is  white  and  nearly  pure.  Further  purification  is 
done  by  dissolving  in  least  sufficient  quantity  of  hot  water  and 
letting  the  filtrate  spontaneously  evaporate  to  dryness. — For  ted 
the  directions  are  nearly  the  same,  except  that  a  coarse  powder 
is  taken,  no  alcohol  is  used,  and  the  larger,  more  dilute  portion 
of  the  percolate  is  concentrated  by  itself. — For  coffee  the  method 
was  the  same  as  for  tea  (exhausting  with  water),  except  that  when 
the  percolate  had  been  nearly  evaporated  60  c.c.  of  alcohol  were 
added,  and  the  resulting  precipitate  filtered  out  and  washed  with 
a  mixture  of  alcohol  3  and  water  1,  when  the  entire  filtrate  was 
evaporated  to  20  c.c.  This  treatment  is  adopted  to  prevent  the 
gelatinizing  of  the  albuminous  matter  by  the  chloroform. 

(3)  COMMAILE  directs  to  prepare  5  grams  of  the  material  with 
1  gram  of  calcined  magnesia  in  a  firm  paste,  which  is  to  stand  24 
hours,  and  is  then  dried  on  the  water  bath  [or  in  an  air-bath  be- 
low 80°  C.]  and  powdered.     It  is  then  exhausted  with  boiling 
chloroform  [applied  in  an  extraction  apparatus,  from  the  receiver 
of  which  the  chloroform  is  then  distilled]   and  the  residue  dried 
[at  a  gentle  heat].      10   grams  of  powdered  glass,  previously 
washed  with  dilute  hydrochloric  acid,  are  then  added,  with  hot 
water,  which  is  then  boiled,  well    shaken  with  the  glass  and 
poured  on  a  wet  filter.     The  residue  is  exhausted  by  washing 
with  portions  of  hot  water.     The  united  filtrates  are  evaporated 
in  a  tared  flask  [exhausted  by  a  pump,  and  dried  at  temperature 
not  above  78°  C.] 

(4)  BLYTH  proposes  the  sublimation  of  the  caffeine  from  a  paste 
of  the  aqueous  extract  mixed  with  magnesia,  thinly  spread  on 
a  thin  iron  plate,  and  covered  with  a  tared  glass  funnel — the  heat 
very  gentle  at  first   and  very  gradually  raised  to  about  200°  C., 
until  a  fresh  funnel  will  receive  no  crystals  by  continuation  of 
the  heat  for  half  an  hour.     But  the  author  prefers  to  sublime 
in  vacuum,  obtained  by  a  mercury  pump,  the  paste  being  spread 
on  a  ground  glass  plate,  fitted  with  a  ground  flanged  funnel, 
when  very  gentle  heat  by  a  sand-bath  is  sufficient. 

g. — Tests  for  Impurities. — Caffeine,  gradually  heated  in  a 
portion  of  about  a  grain  in  a  test-tube  over  the  flame,  should 
completely  sublime,  leaving  no  residue,  and  yielding  a  subli- 
mate, usually  melted  nearest  the  heat  and  crystalline  beyond. 
Contact  with  cold  concentrated  sulphuric  acid  should  not  cause 
coloration,  and  on  heating  at  100°  C.  should  darken  but  slowly. 
Coiftr.fi  with  cold  (colorless)  nitric  acid  should  not  give  imine- 


CANTHARIDIN.  83 

diate  coloration.  Caffeine  should  be  colorless,  should  dissolve  in 
10  to  15  times  its  weight  of  boiling  water,  the  solution  remain- 
ing clear  when  diluted  to  80  or  100  times  its  weight  and  cooled, 
and  being  neutral  to  test-papers.  Respecting  presence  of  theo- 
bromine,  see  under  the  latter. 

CAFFETANNIN.     See  TANNINS. 

CANTHARIDIN.  C10H13O4=196.—  The  highly  poison 
ous,  vesicating  principle  of  the  Spanish  Fly  (Lytta  vesicatoria], 
which  contains  about  OA%.  It  is  also  found  in  a  great  rnanv 
other  coleopterous  insects.  The  powdered  insects,  after  being 
moistened  with  acetic  acid,  are  exhausted  with  chloroform  or 
ether ;  the  extract  evaporated  to  dryness ;  the  residue  boiled  with 
carbon  disulphide  (to  remove  fat),  evaporated  to  dryness  with  a 
little  caustic  alkali,  washed  with  chloroform,  acidified,  and  agi- 
tated with  chloroform,  from  which  the  caiitharidin  crystallizes  on 
concentration.  It  may  be  purified  by  recrystallizing  from  alco- 
holic chloroform  or  from  acetic  ether. 

Caiitharidin  crystallizes  in  colorless  prisms  of  the  dimetric 
system  or  in  laminae,  which  become  soft  at  210°  C.  and  melt  and 
sublime  at   218°   C.     It  sublimes,  in  part,  at  180°  C.,  but  vola- 
tilizes at  a  much  lower  temperature  together  with  the  vapor  of 
water,   alcohol,   etc.     It  is  soluble  in  5000  parts  cold  and  380 
parts  boiling  water  (more  readily  when  just  liberated  by  acids) ; 
in  about  3500  parts  cold  and  readily  in  hot  alcohol ;  in  910  parts 
ether;    84  parts  chloroform;   500  parts  benzene;  1666  parts 
carbon  disulphide.     It  is  soluble  in  volatile  and  fat  oils  ;  very 
easily  in  aqueous  alkalies.     It  is  extracted  from  acid  solutions 
by  benzene,   ether,   chloroform,   and   amyl  alcohol.     Potassium 
hydrate  solution  extracts  it  completely  from  its  solution  in  chlo- 
roform ;  and  by  this  means  it  is  easily  purified.     Cantharidin  acts 
as  a  weak  acid,  forming  salts  which  are  (especially  the  combina- 
tions with  the  fixed  alkalies)  easily  soluble  in  water,  and  which 
possess  the  vesicating  property.     Solvents  do  not   extract  the 
cantharidin  from  these  solutions,  but  it  is  precipitated  by  acids. 
Potassium  caniharidate  is  crystallizable,  very  readily  soluble  in 
water,  soluble  in  3300  parts  cold  and  110  parts  boiling  alcohol, 
insoluble  in  ether  and  chloroform.     In  not  too  dilute  solutions, 
the  potassium  and  sodium  salts  give  precipitates  with  barium 
and  calcium  chloride  (white),  copper  sulphate  (green),  nickel 
sulphate  (green),  cobaltous  sulphate  (red),  palladium  chloride 
(yellow,  hair-shaped,  afterwards  crystalline),  lead  acetate,  and 
mercuric  chloride.     Undiluted  sulphuric  acid  dissolves  cantha- 


84  CHELIDONINE. 

ridin  without  decomposing  it.  Concentrated  sulphuric  acid  and 
potassium  dichromate  decompose  it  with  separation  of  green 
chromium  oxide.  0.0001  gram  cantharidin  is  sufficient  to  draw 
a  blister. 

For  finding  the  per  cent,  of  cantharidin  in  Spanish  flies  or 
preparations  containing  them,  DKAGENDOKFF  washes  about  25 
grams  of  the  powder  with  petroleum  ether  till  all  the  fat  is  re- 
moved (counting  0.0108  gram  cantharidin  for  every  100  c.c.  of 
solvent  used),  stirs  the  residue  with  5  grams  magnesia  or  soda,  and 
water,  evaporates  to  dryness  on  the  water-bath,  powders,  adds  25 
c.c.  chloroform,  acidifies  with  dilute  hydrochloric  acid,  and  agi- 
tates with  30  c.c.  ether,  repeating  this  last  operation  four  times 
with  same  quantity  of  ether.  He  washes  the  ether  solution  seve- 
ral times  with  water,  evaporates  to  dryness,  transfers  the  residue 
(with  help  of  a  little  alcohol)  to  a  small  tared  filter,  washes  with 
alcohol,  then  with  2  to  3  c.c.  water,  dries  at  100°  0.,  and  weighs, 
adding  0.007T  gram  for  every  10  c.c.  alcohol,  and  0.0005  gram  for 
every  c.c.  water  used.  According  to  this  method  he  found 
0.348$  in  a  sample  of  powdered  cantharides  ["  Werthbest.,"  106]. 

CAPRIC,  CAPROIC,  AND  CAPRYLIC  ACIDS.     See 

FATS  AND  OILS. 

CARBOLIC  ACID.     See  PHENOL. 
CASTOR  OIL.     See  FATS  AND  OILS. 
CATECHU-TANNIN.     See  TANNTNS. 


CHELIDONINE.  C^H^l^^SSS.—  Found  with  san- 
guinarine  in  the  herb,  unripe  seed-capsules,  and  root  of  the 
celandine  (Chelidonium  majus).  The  root  contains  the  largest 
proportion. 

Crystallizes  in  colorless,  glittering  tablets,  with  two  molecules 
water,  which  are  driven  off  at  100°  C.  It  melts  to  a  colorless  oil 
at  130°  C.  and  volatilizes  with  steam  ;  is  odorless  and  of  a  bitter, 
harsh  taste  ;  alkaline  in  reaction,  forming  colorless,  crystallizable 
salts  which  possess  an  acid  reaction.  The  sulphate  and  phosphate 
are  readily  soluble  in  water.  Chelidonine  is  insoluble  in  water, 
and,  when  crystallized,  soluble  in  ether  and  alcohol  only  after 
continued  boiling  ;  more  soluble  in  chloroform.  Fat  and  vola- 
tile oils  dissolve  it  readily,  benzene  very  slightly.  Amylic  alco- 
hol extracts  it  most  readily  from  solutions  made  alkaline. 

The  alkaline  hydrates  precipitate  the  alkaloid  in  white  flakes 


CITRIC  ACID.  85 

(becoming  crystalline)  from  solutions  of  its  salts.  It  gives  a  pre- 
cipitate with  platinic  chloride,  not  decomposed  by  water,  con- 
taining 17.42— 17.6$  Pt.  Potassio-mercuric  iodide  (MASING  ') 
gives  a  precipitate  C19H18N3O3I.HgI2.  One  c.c.  MAYER'S 
solution  precipitates  0.01675  gram  chelidonine  (DRAGENDORFF2). 
Iodine  in  alcohol  causes  precipitation.  Concentrated  sulphuric 
acid  dissolves  it  with  bright  colors,  green  at  first,  then  brown, 
edged  with  red  and  violet,  and,  in  presence  of  sugar,  with  rose- 
violet  color,  changing  to  cherry-red  and  blue-violet.  Froehde's 
reagent  gives  a  green  color,  changing  to  blue,  brown,  and  black. 
Sulphuric  acid  and  potassium  nitrate  give  a  green  to  blue  color 

(KlJGELGEN,  1885). 

The  alkaloid  is  obtained  from  the  root  by  precipitating  the 
acidulated  (H2SO4)  water  extract  of  the  root  with  ammonia,  dis- 
solving out  the  sanguinarine  by  means  of  ether  (the  chelidonine 
is  only  very  slightly  soluble),  then  dissolving  the  residue  in  as 
little  as  possible  acidulated  (H2SO4)  water,  and  adding  twice  the 
volume  of  concentrated  hydrochloric  acid,  which  precipitates  the 
hydrochlorate  (soluble  in  325  parts  water).  This  is  decomposed 
by  dilute  ammonia,  and,  after  purification  by  redissolving  in  acidu- 
lated water  and  repeating  the  above  process  as  often  as  may  be 
necessary,  is  crystallized  from  boiling  alcohol  (WITTSTEIN). 

CITRIC  ACID.  H3C6H5O7=192.  Citronensaure.— Found 
in  the  greater  number  of  the  most  acidulous  fruits ;  abundant 
in  tomatoes,  currants,  gooseberries,  raspberries,  strawberries, 
blackberries,  bilberries  (GRAEGER,  1873),  and  tamarinds,  and 
common  in  various  parts  of  plants ;  occurring  for  the  most  part 
as  free  acid,  but  also  as  acid  salts.  Manufactured  from  lemons 
and  from  limes,  both  which  contain  about  5  per  cent.,  or  10  per 
cent,  of  the  juice  (STODDARD,  1868),  and  from  sour  oranges  of 
Florida  and  bergamot  oranges  of  southern  Europe,  no  interfer- 
ing acids  being  present  in  these  sources.8  Cranberries  contain 
over  2  per  cent.,  with  no  other  acid  ;4  unripe  gooseberries,  1  per 
cent. ;  and  the  red  currant,  about  1.3  per  cent.5  Used  chiefly  in 

1  Jour.  Chem.  Soc.,  1877,  i.  477.  2  "  Werthbestimmung, "  p.  102. 

3  Warington  (Jour.  Chem.  Soc.,  xxviii.  937)  found  in  lemon-juice,  lime- 
juice,  and  bergamot-juice  formic  and  acetic  acids,  and  some  non- volatile  acid 
giving  soluble  calcium  salt. 

*L.  W.  MOODY  and  the  author  :  Am.  Jow.  Phar.,  50  (1878),  566. 

5  Hager's  "  Pharmaceutische  Praxis,"  I.,  52.,  with  directions  for  manufac- 
ture. For  lists  of  plants  containing  citric  acid  see  Hager's  "  Untersuchungen," 
II.  109  ;  Husemann's  "Pflanzenstoffe,"555  ;  Gmelin-Kraut's  "  Handbuch,"  v. 
827.  SILVESTRI,  1869 :  Jour,  de  Phar.  et  de  Chim.  [4],  x.  305,  reports  1  to  1^ 
per  cent,  citric  acid  in  Cyphomandra  betacea,  Mexico  and  South  America. 


86  CITRIC  ACID. 

articles  of  food  and  medicine,  but  also  to  some  extent  to  inten- 
sify certain  colors  and  to  remove  mordants  in  dyeing. 

Citric  acid  is  characterised  by  its  crystallization  (a) ;  by  its 
reactions  with  calcium  and  lead  salts,  its  barium  salt  in  well- 
marked  crystals,  and  a  color  reaction  with  ammonia  (d\  also  by 
the  limits  of  its  reducing  power  (d).  From  Tartaric  acid  it  is 
distinguished  by  its  crystallization,  its  failure  to  give  caramel 
odor  when  heated  (Tartaric  acid,  a\  and  its  weaker  reducing 
power  with  chromate,  etc.  (d),  and  is  well  separated  by  not  pre- 
cipitating with  potassium  (Tartaric  acid,/1).  From  ordinary  fruit 
acids  it  is  approximately  separated,  by  treatment  of  lime  salts,  in 
the  scheme  given  under  Malic  acid,  e.  Other  separations  are 
noted  at  e,  p.  88.  Estimation,  by  volumetric  alkali,  and  from 
weight  of  barium  precipitate  (f,  p.  88) ;  in  fruit  juices,  by  direc- 
tions under  Tartaric  acid.  Commercial  forms  and  impurities  are 
noted  at  ^,  p.  89. 

a. — Citric  acid  crystallizes,  from  water  solutions  in  the  cold, 
as  C6H8O7.HoO=210,  and  this  is  the  hydration  of  the  acid  of 
commerce.1  In  very  moist  air  the  crystals  deliquesce  slightly ; 
at  temperatures  from  28°  to  50°  C.  they  effloresce,  and  then  at 
100°  C.  become  anhydrous ;  but  exposed  at  once  to  heat  of 
100°  C.  the  crystals  melt.  From  boiling  and  saturated  solution 
anhydrous  crystals  are  obtained.  The  hydrated  crystals  are  large, 
water-clear,  right  rhombic  (trimetric)  prisms. — At  about  175°  C. 
citric  acid  decomposes,  giving  off  pungent  vapors,  containing 
Acetone,  while  Aconitic  acid  (soluble  in  ether)  is  formed  in 
the  residue  and  then  decomposed  (C6H8O7=C6H6O6-f-H2O). 

b. — Citric  acid  is  soluble  in  its  weight  of  water  at  com- 
mon temperature,  and  in  half  its  weight  of  boiling  water ;  in 
about  its  own  weight  of  ninety  per  cent,  alcohol ;  insoluble  in 
absolute  ether  or  chloroform,2  and  but  slightly  soluble  in  phar- 
macopoeial  stronger  ether  or  chloroform.  Its  water  solution  is 
inactive  to  the  plane  of  polarized  light.  Standing  in  water 
solution  it  decomposes,  and  then  gives  misleading  reactions  of 
reduction. 

o. — Citric  acid,  tribasic,  forms  normal  salts,  acid  salts  of  one- 
third  and  two-thirds  basal  hydrogen,  and  basic  double  salts.  The 
alkali  metal  salts  are  freely  soluble  in  water;  iron,  zinc,  and  cop- 

'8.57  per  cent,  of  water.  Warington  (Jour.  Chem.  Soc.,  xxviii.  [1875], 
927)  found  8.72  per  cent,  as  the  mean  of  17  representatives,  with  8.46  per  cent. 
and  9.35  per  cent,  as  extreme  ranges. 

2  Soluble  in  44  parts  ether,  at  15°  C. — BOURGOIN:  Zeitsch.  an.  Chemie,  17 
(1878),  502,  from  $ull.  Soc.  Chim.  Paris,  £9,  242. 


CITRIC  ACID.  87 

per  normal  citrates  moderately  soluble ;  other  non-alkali  normal 
citrates  mostly  insoluble.  Calcium  citrate  is  somewhat  soluble 
in  cold,  nearly  insoluble  in  hot  water.  Citrate  precipitates  dis- 
solve in  citric  and  other  acids  by  formation  of  soluble  acid 
citrates  ;  and  dissolve  in  alkali  hydrate  solutions  by  forming 
basic  double  salts,  such  as  the  "  soluble "  citrate  of  iron  and 
ammonium  of  pharmacy.  Citric  acid  prevents  the  alkali  preci- 

Eitation  of  most  heavy  metals,  the  soluble  double  salts  being 
Drmed.  Indeed,  numerous  precipitations  are  prevented  or  hin- 
dered by  presence  of  alkali  citrates,1  including  most  carbonates, 
phosphates  (not  ammonio  magnesium),  oxalates,  sulphates,  lead 
and  barium  chromates,  ferric  ferrocyanide,  lead  iodide  and  bro- 
mide, and  arsenious  sulphide.  On  the  contrary,  zinc  and  mag- 
nesium hydrates,  lead  sulphide,  and  most  silver  precipitates  are 
not  affected  by  citrates.  Barium  sulphate  is  precipitated  in  pre- 
sence of  citrates  only  on  boiling.  Equal  basal  proportions  of 
citrate  and  of  the  precipitates  most  favor  their  solution,  which 
seems  to  be  due  to  the  formation  of  double  salts. — Alkali  citrates 
are  sparingly  soluble  in  hot  alcohol,  less  soluble  in  cold  alcohol. 

d. — Solution  of  lime,  added  to  solution  of  citric  acid  to  alka- 
line reaction  or  to  citrates,  causes  no  precipitate  in  the  cold  (dis- 
tinction from  Tartaric,  Raceinic,  Oxalic  acids) ;  but  on  boiling  a 
slight  precipitate  is  formed  (distinction  from  Malic  acid).  Solu- 
tion of  chloride  of  calcium  does  not  precipitate  solution  of  free 
citric  acid  even  on  boiling,  nor  citrates  in  the  cold,  but  precipi- 
tates citrates  (neutralized  citric  acid)  when  the  mixture  is  boiled. 
The  precipitate,  Ca3(C6H5O7)2 .  2H2O,  is  insoluble  in  cold  solution 
of  potassa  (which  should  be  not  very  dilute  and  nearly  free  from 
carbonate),  but  soluble  in  solution  of  cupric  chloride  (two  means 
of  distinction  from  Tartaric  acid)  ;  also  soluble  in  cold  solution 
of  chloride  of  ammonium  and  readily  soluble  in  acetic  acid. — 
Solution  of  lead  acetate  precipitates  from  solutions  of  neutral 
citrates,  and  from  even  very  dilute  alcoholic  solution  of  citric 
acid,  the  white  citrate  of  lead,  Pb3(C6H5O7)2 . iH2O,  somewhat 
soluble  in  free  citric  acid,  soluble  in  nitric  acid,  in  solutions  of 
all  the  alkaline  citrates  and  of  chloride  and  nitrate  of  ammonium, 
soluble  in  ammonia  (formation  of  basic  ammonium  lead  citrate). 
(Malate  of  lead  is  not  soluble  in  malate  of  ammonium). — The 
precipitation  with  barium  is  given  in  d.  But  if  now  the  solution, 
with  excess  of  barium  acetate  (and  a  little  free  acetic  acid— 
FRESENIUS),  be  heated  about  two  hours  on  the  water-bath,  the 

1  J.  SPILLER:  Jour.  Chem.  Soc.,  10,  110;  Phar.  Jour.  Trans.,  [3]  17,  282; 
Jahr.  der  Chemie,  1857,  569. 


88  CITRIC  ACID. 

barium  citrate,  as  Ba3(C6H5O7)2.3|H2O,  crystallizes  in  clino- 
rhombic  prisms  (Kammerer '). 

A  color-test  for  citric  acid  is  made  by  heating  with  ex- 
cess of  ammonia- water — as  5  grams  of  the  acid  to  30  c.c.  am- 
monia-water— in  a  sealed  tube,  at  120°  C.,  for  six  hours.3  On 
exposure  to  the  air  and  light  in  an  evaporating-dish  the  solution 
turns  blue,  slowly  changing  to  green  and  becoming  colorless. 
Usually  .small  crystals  form  in  the  heated  tube  and  afterward  dis- 
appear. At  150°  C.  the  solution  turns  green  in  the  tube,  but  at 
160°  C.  the  reaction  is  not  obtained.  Tartaric,  oxalic,  and  malic 
acids  do  not  interfere.  The  least  quantity  of  citric  acid  revealed 
by  the  test  is  0.010  gram. 

Nitrate  of  silver  precipitates  from  neutral  solutions  of  ci- 
trates white  normal  citrate  of  silver,  not  blackened  by  boiling 
(distinction  from  Tartrate). — Solution  of  permanganate  of  po- 
tassium is  scarcely  at  all  affected  by  free  citric  acid  in  the  cold. 
"With  free  alkali  the  solution  turns  green  slowly  in  the  cold, 
readily  when  boiled,  without  precipitation  of  brown  binoxide  of 
manganese  till  after  a  long  time  (distinction  from  Tartrate). — 
Dichromate  of  potassium  solution  is  not  reduced  by  citric  acid 
(distinction  from  Malic,  etc.) 

e. — Citric  acid  is  separated  from  acids  making  soluble  lead 
salts,  through  precipitation  with  lead  acetate  and  subsequent 
treatment  with  hydrogen  sulphide.  From  tannins  and  gallic 
acid,  as  noted  under  Gallotannin.  Insoluble  citrates  are  con- 
verted to  alkali  citrates,  as  noted  under  gravimetric  estimation, 
below. 

f. — The  additnetry  of  citric  acid,  with  litmus  as  an  indicator, 
can  be  accurately  done  only  by  standardizing  the  alkali  solution 
with  weighed  pure  crystallized  citric  acid,  using  the  same  litmus- 
paper  and  holding  the  same  conditions  both  in  standardizing 
and  in  the  estimation.3  Warington  states  that  the  litmus  color 
"  changes  in  a  perfectly  gradual  manner,"  that  "  the  amount  of 
alkali  used  is  a  little  less  than  that  required  by  theory  to  form 
trisodic  citrate,"  and  "  the  more  delicate  the  litmus-paper  the 
nearer  does  the  experiment  approach  "  a  neutral  reaction  for  the 
normal  salt.  But  with  phenol-phthalein  as  an  indicator  sharp 
results  are  obtained,  the  end  reaction  being  exactly  at  formation 

1  Zeitsch.  anal.  Chemie,  8,  298,  with  cuts  of  the  crystals. 

2  SABANIN  and  LASKOWSKY:   Zeitsch.  anal.  Chemie,    17  (1878),  73;  Jour. 
Chem.  Soc.,  1878,  Abs.,  342.    The  reaction  was  declared  earlier  in  a  Russian 
Dissertation  by  Sarandinaki,  and  in  Ber.  d.  chem.  Ges.,  5(1872),  1100. 

3  WARINGTON:  Jour.  Chem.  8oc.t  28  (1875),  929,  927. 


CITRIC  ACID.  89 

of  K3C6H5O7,  or  the  corresponding  sodium  salt.1  In  production 
of  this  normal  salt  each  c.c.  of  a  normal  alkali  solution  represents 
0.070  gram  crystallized,  or  0.064  of  anhydrous  acid. 

For  gravimetric  estimation  the  precipitation  most  approved 
is  that  of  barium  citrate,  to  be  weighed  as  sulphate.2  It  is  most 
complete  in  solution  of  alcohol  of  0.908  specific  gravity.  Pre- 
viously the  citric  acid  is  obtained  as  alkali  citrate ;  if  free,  by 
neutralization  with  soda ;  if  combined  with  a  non-alkali  base,  by 
warm  digestion  with  an  excess  of  sodium  hydroxide  or  potassium 
hydroxide,  filtering  and  washing — the  filtrate  being  neutralized 
by  acetic  acid.  In  either  case  the  carefully  neutralized  and  not 
very  dilute  solution  is  treated  with  a  slight  excess  of  exactly 
neutral  solution  of  acetate  of  barium,  and  a  volume  of  95  per 
cent,  alcohol,  equalto  twice  that  of  the  whole  mixture,  is  added. 
The  precipitate  is  washed  on  the  filter  with  63  per  cent,  alcohol, 
and  dried  at  a  moderate  heat.  The  citrate  of  barium  contains  a 
variable  quantity  of  water,  and  is  transformed  into  sulphate  of 
barium  by  transferring  to  a  porcelain  capsule,  burning  the  filter, 
and  heating  with  sulphuric  acid  several  times  till  the  weight  is 
constant.  3BaSO4  :  2H3C6H5O7 .  H2O : :  1  :  0.601.  Hager  di- 
rects that  barium  or  calcium  citrate  (washed  with  alcohol)  be 
dried  at  120°  to  150°  and  weighed. 

Ba3(C6H5O7)2  :  2H3C6H5O7 .  H2O : :  1  :  0.53232. 

For  estimation  in  Fruit  Juices  see  Tartaric  acid,/"  (Waring- 
ton,  Fleischer). 

g. — In  commerce  the  first  form  of  citric  acid  is  concentrated 
lemon-juice,  lime-juice,  and  bergamot-juice,  sometimes  contain- 
ing alcohol  added  for  preservation,  and  liable  to  contain  formic 
and  acetic  acids  from  decomposition.  Crude  calcium  an<  mag- 
nesium citrates  are  made  for  transportation.  In  the  citric  acid 
manufacture  normal  calcium  citrate  is  precipitated,  and  this  is 
transposed  with  dilute  sulphuric  acid.  Among  impurities  tar- 
taric  acid  is  the  most  frequent  adulteration,  being  sometimes 
substituted  altogether  in  some  medicinal  preparations,  especially 
in  dry  "  citrate  of  magnesia."  Lead  may  be  present  from  manu- 
facture or  storage,  and  calcium  salt  and  traces  of  sulphuric  acid 
may  be  left  from  manufacture. — The  detection  of  Tartaric  acid 
may  be  done  by  its  potassium  precipitation,  applied  as  described 
under  that  acid  at  d,  or  by  its  reduction  of  dichromate  in  the 
way  specified  under  Tartaric  acid,  d.  Phosphoric  acid  is  said  to  be 

1  THOMSON,  1883:  Chem.  News,  47,  135;  Jour.  Chem.  8oc.,  44,  826. 

2  J.  CREUSE:  American  Ch&mist,  I  (1871),  424;  Zeitsch.  anal.  Chemie.  n 
(1872),  446. 


90  CINCHONA    ALKALOIDS. 

sometimes  present  in  the  citric  acid  of  commerce  (BAKFOED).     It 
is  most  clearly  detected  after  calcining  the  alkali  salt. 

CHAIRAMIDINE  and  CHAIRAMINE,  CHINOI- 
DINE,  CRINOLINE.  See  CINCHONA  ALKALOIDS. 

CHRYSAMMIC  ACID.     See  ALOINS. 
CINCHAMIDINE.     See  CINCHONA  ALKALOIDS. 

CINCHONA  ALKALOIDS.— Alkaloids  of  the  bark  of 
species  of  Cinchona  and  certain  allied  genera  of  the  cinchoneae. 
In  the  leaf  and  wood  in  very  small  quantities ;  most  abundant  in 
the  bark  of  the  root. 

CONTENTS  : — List  of  alkaloids,  with  description  of  those  not  used ;  the  com- 
mercial alkaloids ;  the  amorphous  alkaloids  and  chinoidine ;  yield  of  the  total 
and  several  alkaloids  in  different  barks;  chemical  constitution;  tabular  com- 
parison of  characteristics;  enumeration  of  means  of  analytical  distinction  ;  mi- 
cro-chemical distinctions ;  separation  and  estimation  of  total  alkaloids,  (1)  the 
plan  of  Prollius,  (2)  by  extraction  apparatus,  (3)  by  amyl  alcohol,  Squibb's 
process,  the  Br.  Ph.  process,  (4)  by  ethyl  alcohol,  the  U.  S.  Ph.  process ;  sepa- 
ration of  the  alkaloids  from  each  other,  enumeration  of  methods;  quinine  sepa- 
ration as  sulphate  in  detail ;  separation  by  ether,  Liebig's  plan ;  by  ammonia, 
Kerner's  plan ;  cinchonidine  separation,  as  tartrate,  with  subsequent  removal 
of  quinine;  De  Vrij's  process;  Muter's  method;  rotatory  power  of  the  alkaloids, 
in  methods  of  estimation. — Quinine,  analytical  outline ;  (a)  crystals  and  heat- 
reactions  of  the  alkaloid  and  its  salts :  (6)  taste  and  physiological  effects ;  (c) 
solubilities  of  the  alkaloid  and  its  salts;  (d)  qualitative  tests  and  their  limits; 
(e)  separations  in  general,  from  pills;  (/)  quantitative  methods,  gravimetric, 
volumetric,  in  herapathite;  (g)  tests  for  impurities;  Kerner's  quantitative 
method;  the  pharmacopoeia!  tests  of  U.  S.,  Germ.,  Fran.;  ammonia  test  of 
salts  other  than  sulphate,  and  of  the  free  alkaloid  and  bisulphate ;  test  of  efflo- 
resced salts;  Hesse's  test;  history  of  Liebig's  test;  Br.  Ph.  tests;  water  of  crys- 
tallization of  sulphate. — Quinidine,  nomenclature,  analytical  outline;  (a)  crys- 
tals and  heat-reactions;  (c)  solubilities;  (d)  qualitative  tests;  (e)  separations; 
{/)  quantitative  work;  (g)  tests  of  purity. — C'inchonidine,  analytical  outline; 
(a)  crystals  and  heat-reactions ;  (6)  effects ;  (c)  solubilities ;  (d)  qualitative  tests ; 
(e)  separation;  (/)  estimation;  (g)  tests  of  purity. — Cinchoni/ne,  analytical  out- 
line; (a)  crystals  and  heat-reactions;  (c)  solubilities;  (d)  qualitative  tests;  (e) 
separations;  (/)  estimations;  (g)  tests  of  purity. — Qmnoline,  production;  (a) 
forms  and  heat-reactions;  (5)  effects;  (c)  solubilities;  (d)  qualitative  tests; 
tests  for  impurities. — Kairines,  constitution  and  production,  description  and 
means  of  identification. — Thfillim,  constitution,  description. — Antipyrine,  con- 
stitution, description,  tests,  and  impurities. 

(Crystallizable  alkaloids  in  italic;  amorphous  alkaloids  in  Roman.) 

Quinine,   C20H24N2O2.      Pelletier   and   Caventou,   1820.      See 

p.  125. 
Quinidine,  C20H24N2O2.   Yon  Hei jningen ,  1 849.    ( Conchinine  of 

HESSE.)     See  p.  154. 


CINCHONA   ALKALOIDS.  91 

Cinchonine,  C-LQK22N2O.1  Pelletier  and  Caventou,  1820.  See 
Index. 

Cinchonidine^  C^IL^NgO.1  Henry  and  Delondre,  1833  ; 
Winckler,  1844;  HESSE. 

Diquinicine,  C40H46N4O3.  HESSE,  1878.  Diconchinine.  Apo- 
diquinidine.  The  chief  amorphous  alkaloid  existing  in 
barks  and  found  in  chinoidine  of  commerce  (p.  94).  Fluo- 
resces  in  sulphuric  acid  solution  ;  gives  the  thalleioquin 
reaction  ;  rotates  to  the  right ;  forms  only  amorphous  salts  ; 
and  does  not  yield  quinicine.  Its  relation  to  quinine  or  qui- 
nidine  is  shown  by  the  equation :  2C20H24N2O0  —  H2O 
=C40H46N403. 

Dicinchoriicine.  HESSE,  1878.  Dichonchonine.  Apo-dicincho- 
nine.  Derived  from  cinchonidine  and  cinchonine ;  found 
in  chinmdine  of  commerce ;  probably  existing  in  amorphous 
condition  in  the  bark ;  has  not  been  completely  isolated. 
(C38H42N4O?)  See  Amorphous  Alkaloids  of  Cinchona, 
p.  94. 

[Quinicine,  C20H24N2O2.  PASTEUR,  1853 ;  HOWARD,  1872 ; 
HESSE,  1878.  Formed  by  melting  sulphates  or  other  salts 
of  quinine  or  quinidine.  Also  by  action  of  light.  Not 
found  in  cinchona  barks.  Not  fluorescent.  Gives  the  thal- 
leioquin reaction.  Rotates  feebly  to  the  right.  Amorphous, 
but  can  give  rise  to  certain  crystalline  salts.] 

[Cinchonicine,  C19H22N2O.  PASTEUR,  1853;  HOWARD,  1872; 
HESSE,  1878.  Formed  by  melting  sulphates  or  other  salts 
of  cinchonine  or  cinchonidine.  Not  contained  in  cinchona 
barks.  Rotates  to  the  right.  Amorphous,  but  forms  some 
crystalline  salts.] 

Hydroquinine,  C20H2gN2O2.  HESSE,  1882.  Fluoresces.  Gives 
thalleioquin  reaction.  Rotates  to  the  left. 

Hydroquinidine,  C20H26N2O2.  HESSE,  1882  ;  FORST  and  BOH- 
RINGER,  1882.  Accompanies  the  quinidine  of  commerce. 
Also  formed  by  action  of  permanganate  on  quinidine.  Ro- 
tates to  the  left.  Fluoresces.  Gives  the  thalleioquin  reac- 
tion. 

Hydrocinchonidine,  C19H24N2O.  HESSE,  1882.  Found  in  com- 
mercial cinchonidine  (when  this  is  not  in  loose  needles). 
Rotates  to  the  left.  Not  fluorescent.  The  pure  base  melts 
below  100°  C.  Heated  with  acids  it  becomes  amorphous. 

'SKRAUP,  1877;  LAURENT,  1848.  The  formula  C20H24]Sr20,  which  has 
been  long  accepted,  is  from  REGNAULT,  and  supported  by  Hlasiwetz,  1851. 
Skraup:  CJiem.  Ctntr.,  1877,  629;  Liebig's  Annalen,  197,  226. 


92  CINCHONA   ALKALOIDS. 

In  the  bark  of  Remijia  Purdieana  and  R.  pedunculata   (C. 

cuprea).1 

Quinamine,  C19H24N2O2.     (Found  in  other  barks,  though  most 

abundant   in   u  cuprea"    bark.)      Dextrorotatory.      HESSE, 

1872,  1877  ;  OUDEMANS,  1879.     With  sulphuric  acid  and  a 

trace  of  nitric  acid,  colors  orange  to  red. 
Conquinamine*  C19H24N2O2.     Quinidamine.     Accompanies  qui- 

namine.     HESSE,  OUDEMANS,  1881. 

Quinamidine  and  Quinamicine,  amorphous  isomers  of  quinamine. 
Homoquinine.     In  "  cuprea  bark.-  '     A  compound  of  Cupreine, 

C19H22N2O2,  and  quinine,  into  which  two  alkaloids  it  splits 

and  from  which  it  may  be  synthesized.    Levorotatory.    PAUL 

and  COWNLEY,  1881,  1885  ;  Hesse,  1885." 
Cinchonamine,    C19H24N2O.      ARNAUD,    1881,    1885  ;     HESSE, 

1885  ;     SEE   and   HOCHEFONTAINE,    1885.      Dextrorotatory. 

Colored  reddish-yellow  by  sulphuric,  yellow  by  nitric  acid. 

With  nitrates  forms  characteristic  insoluble  crystals  ;  hence 

proposed  as  a  test  for  nitrates  (Phar.  Jour.  Trans.,  [3],  15, 

772).     Of  a  strong  toxic  effect. 
Cusconine,  C23II26N2O4.     HESSE,  1877,  in  barks  shipped  from 

Cusco,   in   Peru.     Difficult   of   crystallization.      Rotates  to 

the  left.     Accompanies  Aricine. 
Concusconine,    C23H26N2O4.      HESSE,    1883.       Dextrorotatory. 

With  sulphuric  acid  gives  a  green  color.      Free  alkaloid  is 

tasteless. 

Chairamine,  C22H26N2O4.     HESSE,  1884.      Dextrorotatory. 
Conchavramwe,  C22H2gN2O4.     HESSE,  1884.     Dextrorotatory. 
Chairamidine,  C22H261N2O4.     HESSE,  1884.      Amorphous.     Dex- 

trorotatory. 
Conchairamidine,  C22H2&N2O4.      HESSE,   1884.      Levorotatory. 

Turns  green  with  sulphuric  acid. 

In  other  barks. 

Paytine,  C21H24N2O.  In  1870,  from,  a  white  Cinchona  bark 
from  Payta~.  Levorotatory.  With  chlorinated  lime  gives  a 
dark  red  color.  See,  further,  WuLFSBEKa,  1880." 

Aricine,  C23H28N2O4.  HESSE,  1879.  PELLETIEE  and  CORIOL, 
in  1829,  in"  a  bark  from  Arica.  Found  by  HESSE,  in  1882, 
in  l(  cuprea"  bark.  Levorotatory.  Not  bitter,  astringent 
taste  (Husemann's  "Pflanzenstoffe"). 


Hesse's  summary:  Jour.  Chem.  Soc.,  1885,  Abs.,  64. 
P7iar.  Jour.  Trans.,  [3],  15,  221, 
*Phar.  Jour.  Trans.,  [3],  n,  269. 


*P7iar.  Jour.  Trans.,  [3],  15,  221,  401.    Liebig's  Annalen,  230,  55. 
.,  [3], 


CINCHONA   ALKALOIDS.  93 

Paricine,  C16H18N2O.      Winckler,   1845.     In  bark  from  Para. 

FLUCKIGER,  1870. 
Cinchotine,  C19H24N2O.     The  Hydrocinchonine  of  WILLM  and 

CAVENTOU.       Accompanies    cinchonine.       Dextrorotatory. 

SKRAUP,  1879.     FORST  and  BOHRINGER  (1882)  find  it  not  an 

oxidation  product,  as  they  had  before  stated  (1881). 
Owohamidine,  C^H^IS^O.     Accompanies  cinchonidine.    Levo- 

rotatory.     HESSE,  1881. 

The  existence  of  Homocinchonidine  (HESSE,  1 877)  is  denied  by 
SKRAUP  (1880).  Hesse's  Hydroeonquinine  is  believed  by  FORST 
.and  BOHRINGER  to  be  identical  with  hydroquinidine.  Hesse  (1885) 
reports  that  the  substance  previously  (1883)  named  by  him  as 
Concusconidine  proves  to  be  a  mixture  of  alkaloids.  Paytamine 
is  an  amorphous  alkaloid  accompanying  Pay  tine. 

Of  artificial  products,  the  purpose  of  this  work  requires 
description  of  only 

Quinoline,  C9H7N.    Produced  from  cinchonine  and  other  sources. 

See  Index. 

Kairines,  C10H13NO.     Derivatives  of  quinoline. 
Thalline,  C10H13NO.     A  methyl  kairine. 

The  list  of  natural  cinchona  alkaloids  above  given  is  designed 
to  include  all  those  whose  separate  identity  remains  established, 
by  the  evidence  published,  up  to  1886,  but  some  omissions  may 
have  been  made.  The  artificial  derivatives,  oxidation  products, 
etc.,  are  excluded  from  the  list  above,  and  have  only  a  brief 
general  history  under  Chemical  Constitution  of  Cinchona  Alka- 
loids. It  will  be  observed  that  the  present  chemistry  of  cinchona 
alkaloids  agrees  with  the  chemistry  following  the  work  of  Winck- 
ler in  1847  and  Pasteur  from  1853,  in  the  fundamental  ouir 
lines  affecting  the  alkaloids  in  use,  those  most  abundant  in  barks 
of  the  cinchona  family  as  a  whole.  It  is  stated  now,  as  it  was 
over  thirty  years  ago,  that  the  two  isomers  quinine  and  quinidine, 
with  the  two  isomers  cinchonine  and  cinchonidine,  constitute 
the  greater  part  of  the  crystallizable  alkaloids  of  the  cinchonas. 
All  the  crystallizable  alkaloids  in  use  under  pharmacopoeia! 
authority  are  carried  under  these  four  names.  In  elementary 
constituents,  cinchonine  and  cinchonidine  have  each  one  atom  of 
oxygen  less  in  the  molecule,  and,  according  to  recent  determina- 
tions, have  each  CH2  less  in  the  molecule  than  quinine  and  qui- 
nidine:  C^H0^202— C19H22N2O=:CH2+O. 

To  a  limited  extent  other  crystallizable  alkaloids  of  cinchona 
are  certainly  carried  into  use  under  the  names  of  the  four  princi- 
pal alkaloids.  It  is  specifically  stated  that  hydroquinidine  ac- 


94  CINCHONA    ALKALOIDS. 

companies  commercial  quinidine  ;  that  hydrocinchonidine  and 
cinchamidine  are  found  with  commercial  cinchonidine,  and  that 
cinchotine  sometimes  contaminates  cinchonine.  Hydroquinine 
may  go  with  manufactured  quinidine  or  quinine,  being  found  in 
the  mother-liquors  of  the  former.  Quinamine,  and  probably 
conquinamine,  are  found  in  other  barks  besides  "  cuprea  "  bark, 
and  may  find  their  way  into  manufactured  salts,  where  they 
should  then  be  detected  by  reactions  with  sulphuric  and  nitric 
acids.  Then  the  amorphous  products  quinicine  and  cinchonicine 
may  be  carried  into  crystalline  forms  of  salts  to  some  extent. 
And  it  is  always  understood  that  separations  of  cinchona  alka- 
loids in  manufacture  are  not  absolute,  so  that  the  quinine  salts  of 
the  market  always  contain,  under  certain  limits,  cinchonidine 
and  cinchonine,  perhaps  quinidine,  and  under  narrower  limits 
may  contain  the  amorphous  alkaloids  in  general.  The  quinidine 
of  commerce,  according  to  Hesse,  1875,  consists  most  often  of 
cinchonidine  with  a  little  quinine. 

Amorphous  cinchona  alkaloids. — The  name  Chinoidine  (Qui- 
noidine)  was  given  by  Sertiirner,  in  1828,  to  the  amorphous  alka- 
loidal  substance  left  after  separating  quinine  and  cinchonine  as 
then  known,  and  which  he  believed  to  be  a  distinct  alkaloid. 
Chinoidine  was  recognized  as  an  easily  fusible  base,  of  strong 
alkalinity,  forming  uncrystallizable  salts,  and  of  full  virtues  as  a 
febrifuge.  Until  about  1855  it  was  prepared,  in  connection  with 
the  crystallizable  alkaloids,  by  uniform  methods,  from  Calisaya 
barks  of  good  strength,  and  therefore  possessed  a  fairly  constant 
character.  About  1847  Winckler  stated  that  chinoidine  was  in 
large  part  an  amorphous  transformation  product  of  the  crystalli- 
zable alkaloids  of  cinchona  then  known.  During  investigations 
commencing  about  1853  Pasteur  made  it  known  that  by  fusing 
for  some  time  a  salt  of  one  of  the  crystallizable  alkaloids,  or,  in 
part,  by  hot  digestion  in  acidulous  solution,  an  amorphous  modi- 
fication is  obtained,  without  change  of  elementary  composition. 
The  amorphous  product  of  quinine  and  of  quinidine  he  named 
Quinicine;  and  the  amorphous  product  of  cinchonine  and  of 
cinchonidine  he  named  Cinchonicine  /  and  it  has  been  generally 
believed  that  these  are  the  uncrystallizable  alkaloids  which  exist 
already  formed  in  the  barks,  as  well  as  result  from  chemical  treat- 
ment of  the  barks.  All  barks  contain  amorphous  alkaloids; 
sometimes  the  larger  portion  of  the  alkaloids  is  amorphous.  And 
the  amorphous  alkaloidal  matter  of  cinchona  has  been  in  great 
part  accounted  for  according  to  the  nomenclature  of  Pasteur, 
almost  down  to  the  present  time,  so  that  we  have  had  the  familiar 
classification  of  the  leading  natural  cinchona  alkaloids,  as  follows : 


CINCHONA   ALKALOIDS. 


95 


C20H24^T2O2  :  Quinine,  Quinidine,  [Quinicine]. 
C20H24N2O  :  Cinchonine,  Cinchonidine,  [Cinchonicine]. 

Howard,  in  1872.  found  quinicine  and  cinchonicine,  made 
from  quinine  and  cinchonine,  to  be  capable  of  crystallizable  com- 
binations, while  no  salts  crystallizable  could  be  produced  from 
natural  amorphous  alkaloids.  And  Hesse  affirms  (1878)  that 
quinicine  and  cinchonicine,  as  isomers  of  quinine  and  cinchonine, 
are  not  present  in  the  barks,  are  not  formed  to  any  great  extent 
by  ordinary  methods  of  manufacture,  and  not  found  in  chinoidine. 
They  would  be  formed  in  the  manufacturing  treatment,  the  melt- 
ing of  chinoidine,  only  so  far  as  the  crystallizable  alkaloids  are 
subjected  to  this  treatment,  for  it  is  stated  by  Hesse  that  the 
chief  natural  amorphous  alkaloids,  taken  from  the  bark  or  from 
chinoidine,  are  not  convertible  into  quinicine  or  cinchonicine, 
which  are  partly  crystallizable.  The  most  prominent  natural 
amorphous  alkaloids,  those  making  up  the  larger  part  of  the  by- 
product chinoidine,  according  to  Hesse,  are  (with  a  little  liberty 
in  translating  Hesse's  nomenclature)  diquinicine  and  dicinchoni- 
cine,  amorphous  alkaloids  having  the  constitution  of  anhydrides 
(apo-derivatives)  respectively  of  quinine  and  cinchonine  (see  the 
equation  under  Diquinicine,  p.  91).  In  this  view  the  leading 
natural  cinchona  alkaloids  are  to  be  grouped  as  follows  : 

Crystallizable.  Amorphous. 

C20H24N2O2  :  Quinine,  Quinidine.  C40H46N4O3  :  Diquinicine. 

C19H22N2O  :    Cinchonine,  Cincho-  CggH^J^O  ( ? ) :  Dicincho- 
nidine.  nicine. 

By  heating  the  chief  crystallizable  cinchona  alkaloids  with 
hydrochloric  acid,  at  140°  to  150°  C.,  in  sealed  tubes,  for  6  to  10 
hours,  HESSE  (1880) 1  obtained  an  apo-derivative  from  each. 
Apoquinine  and  apoquinidine  each  had  the  formula  C19H22N2O2 , 
the  removal  of  CH2  being  effected  by  production  of  CH3C1,  and 
both  these  new  alkaloids  were  found  to  be-  amorphous  in  all  their 
salts.  They  gave  the  thalleioquin  reaction,  were  soluble  in  ether 
or  alcohol,  and  showed  fluorescence.  Apocinchonine  and  apo- 
cinchonidine  were  each  C19H22lSr2O,  isomeric  with  cinchonine, 
and  each  was  crystallizable.  But  a  diapocinchonine,  C38H44Ts  2O2 , 
forming  only  amorphous  salts,  was  obtained,  readily  soluble  in 
alcohol,  ether,  or  chloroform,  and,  Hesse  states,  distinct  from  the 
natural  alkaloid  dicinchonicine  (p.  91),  as  well  as  from  cinchoni- 
cine, formed  by  melting. 

1  7?"r.  dent.  diem.  Ues  ,  205,  314;  Jour.  Chem.  Soc.,  1881,  Abs.,  615;  Am. 
Jour  Phar.,  53,  105,  160. 


96  CINCHONA   ALKALOIDS. 

The  amorphous  alkaloids  difficult  of  separation  have  been 
less  satisfactorily  studied  than  the  crystallizable  ones,  and  it  is 
strongly  probable  that  diquinicine  and  dicinchonicine  very  imper- 
fectly represent  the  amorphous  alkaloids  of  the  barks.  Chinoi- 
dine  usually  contains  quinidine  in  proportion  larger  than  that  of 
the  other  crystallizable  alkaloids.  Further  than  this  it  has  as  yet 
only  been  ascertained,  that  quinamidine  and  quinamicine  are 
amorphous  alkaloids  found  in  some  other  barks  besides  those  of 
Remijia ;  and  that  cusconine,  chairamidine,  and  paytamine  are 
amorphous  accompaniments  of  the  special  crystallizable  alkaloids 
of  certain  exceptional  barks.  Elementary  analysis  has  been  ob- 
tained of  all  these  except  paytamine. 

Yield  of  Cinchona  Alkaloids. 

Of  total  alkaloids : 1 
In  barks  of  different  species  and  localities,  from  a  maximum 

of  about  15  per  cent,  to  entire  absence  of  alkaloids. 
"  Calisaya  Ledgeriana,  Java,  80  specimens,  MOENS,  1879, 12.50 

to  1.09  per  cent. 

"  Calisaya  Javanica,  DE  YEIJ,  18T9,  10.3  to  1.3  per  cent. 
"  Cinchona  officinalis,  BROUGHTON,  1872,  6.9  to  3. 1  per  cent. 
"  C.  succirubra,  Java,  1881,  9.8  to  3.2  per  cent. 
"  China  regia,  1855,  0.99  per  cent.     In  China  cuprea,  5.9  to  2 

per  cent. 
"  "Cinchona"  of  U.  S.  Ph.,  dried  at  100°  C.,  at  least  3  per 

cent. 
"  "  Red  Cinchona  Bark "  of  Br.  Ph.,  between  5  and  6  per 

cent. 

"  "  Cinchona  Barks"  of  Ph.  Germ.,  at  least  3|  per  cent. 
"  Cinchona  barks,  Ph.  Fran.,  at  least  2J  per  cent.     In  Red 

barks,  at  least  3  per  cent. 

Of  Quinine : 
In  Cinchona  succirubra,  Java,  harvest  of  1881,  MOENS,  2.5  to 

0.4  per  cent. 

"  C.  Ledgeriana,  Java,  1879,  11.6  to  0.8  per  cent. 
"  C.  officinalis,  India,  1872,  BROUGHTON,  4.18  to  1.6  percent. 
"  "Red  Cinchona"  and  in   « Yellow  C.,"  dried  at  100°  C., 

U.  S.  Ph.,  at  least  2  per  cent. 
"  "  Red  Cinchona  bark,"  Br.  Ph.,  at  least  3  per  cent,  quinine 

and  cinchonidine. 

1  For  a  report  of  the  yield  of  individual  and  total  alkaloids  in  13  Bolivia 
Cinchona  Barks,  see  STOEDER,  1878:  Archiv  d.  Phar.,  [3],  13,  243;  Am.  Jour. 
Phar.,$i,22. 


CONSTITUTION.  97 

In  Red  Cinchona  bark,  Ph.  Fran.,  at  least  2  per  cent,  quinine 
as  sulphate. 

<)f  Cinchonidine : 

In  C.  succirubra,  Java,  harvest  of  1881,  MOENS,  5.2  to  1.3  per 

cent. 
"  C.  Calisaya,  1873,  MOENS,  8  samples,  1.2  to  0.4  per  cent. 

•Of  Cinchonine : 

In  C.  Calisaya,  18T3,  MOENS,  8  samples,  1.1  to  0.1  per  cent. 
"  China  de  Quito  rubra,  REICH AKDT,  0.39  per  cent. 
"  China  Huanuco,  Reichardt,  2.24  per  cent. 

Of  Quinidine : 

In  C.  Calisaya,  1873,  MOENS,  8  samples,  0.9  to  0.86  per  cent. 
"  China   cuprea,   in   comparative   abundance,   Gehe  &  Co., 

1884. 

Constitution  of  Cinchona  Alkaloids. — The  derivation  of  cin- 
ehonine  and  quinine  from  Quinoline,  C9H7N,  inferred  by  Weidel 
in  1873,  has  acquired  additional  light  every  year,  and  promises 
to  become  clearly  understood.  The  remarkable  interest  of  the 
pyridine  series  and  the  derived  quiiioline  series,  in  relation  to 
natural  alkaloids,  is  mentioned  under  Midriatic  Alkaloids,  with 
a  statement  of  the  central  position  of  pyridine  in  the  theoreti- 
cal chemistry  of  natural  alkaloids.  Quinoline  was  obtained  by 
Gerhardt  in  1842  by  distilling  quinine  with  potash,  and  is  so 
obtained  from  certain  other  alkaloids,  cinchonine,  strychnine, 
brucine.  It  is  also  found  in  considerable  quantity  in  the  heavier 
distillates  (dead  oil)  from  coal-tar.  The  hypothetical  formulae  of 
pyridine  and  quinoline,  as  aromatic  compounds  analogous  to  ben- 
zene and  naphthalene,  with  N  in  the  place  of  one  CH  in  the 
benzene  ring  and  naphthalene  double  ring,  was  proposed  about 
1870.  The  midriatic  base  tropine  is  derived  from  pyridine. 
The  synthesis  of  quinoline  has  been  effected  in  several  ways; 
that  by  Skraup  in  1881,  from  aniline,  nitrobenzene,  and  glycerine, 
is  a  practical  working  method,  yielding  quinoline  identical 
with  that  distilled  from  cinchona  alkaloids :  2C6H7N  (aniline) 
-fC6H5NO2  (nitrobenzene)  +  3C3H8O3  (glycerine)  =  3C9H7lSr 
{quinoline)  -(-  11H2O. 

Since  about  1880  there  has  been  a  most  active  interest  in 
the  field  of  pure  chemistry  lying  between  the  quinoline  series 
on  the  one  side  and  the  natural  cinchona  alkaloids  on  the  other 
side.  A  vast  amount  of  well-directed  experimental  work  has 
been  done,  and  great  numbers  of  derivatives,  both  of  the  quino- 
line bodies  and  of  cinchona  alkaloids,  have  been  produced  and 


98  CINCHONA   ALKALOIDS. 

examined.  It  is  an  opinion  sustained  by  men  acquainted  with 
the  methods  and  difficulties  of  organic  synthesis  that  quinine 
will  be  produced  artificially.  Meantime  artificial  quinoline  de- 
rivatives, such  as  those  brought  before  the  world  as  Kairines, 
have  been  found  to  present  physiological  effects  like  those  of 
quinine.  As  to  the  commercial  production  of  quinoline  itself, 
as  a  medicinal  material,  should  its  products  come  into  general 
demand,  it  would  perhaps  continue  to  be  made  from  cinch  onine, 
unless  manufacturers  should  exercise  great  care,  in  its  production 
by  Skraup's  process,  to  avoid  contamination  with  nitrobenzene 
(p.  97). 

It  is  to  be  observed  that  both  pyridine  and  quinoline  bases 
have  the  characteristic  of  holding  H2,  H4,  H6  in  addition  com- 
binations. The  hydrogenized  members  of  the  quinoline  series 
(hydroquinolines),  with  various  substitutions,  take  character  ap- 
proaching that  of  the  natural  alkaloids.  The  gradually  accumu- 
lating evidences,  to  which  references  are  below  given,  render 
probable  the  following  rational  formulae,  with  two  quinoline 
nuclei  in  the  alkaloid  molecule  : 


Cinchonine  :  C9H10N  .  C9H9N  .  v<3  .  CH3)  =C19H22N0O. 

Quinine  :  C9H10N  .  C9H8N  .  (O  .  CR3)2=C20H24N~2O2. 
Both  quinoline  and  pyridine  tend  to  form  tetra-hydrides  ;  and 
tetrahydro-quinoline,  C9H7[H4]N,  or  C9H1]LN,  is  fruitful  of  de- 
rivatives having  resemblances'  to  natural  alkaloids.  In  the  hypo- 
thetical formulae  for  cinchonine  and  quinine,  the  quinoline  tetra- 
hydride  molecules  drop  an  atom  of  hydrogen  for  union  with  each 
other,  arid  another  atom  of  hydrogen  for  each  molecule  of  meth- 
oxide  (O.CH3)  taken.  The  systematic  names,  therefore,  are 
respectively  methoxy-tetrahydro-diquinoline  and  dimethoxy- 
tetrahydro-diquinoline.  1 

'L.  HOFFMAN  and  W.  KONTGS,  1883:  Ber.  deut.  chem.  Ges.,  16,  727;  Jour. 
Chem.  Soc.,  1883,  Abs.,  1143.  KONIGS,  with  COMSTOCK  and  with  FEER,  1885, 
1884,  with  G.  K&BNER,  1884.  KONIGS.  1881:  Ber.  deut.  chem.  Ges.,  14,  1852; 
Jour.  Chem.  Soc.,  1882,  Abs.,  224:  1880:  Ber.  deut.  chem.  Ges.,  13,  911. 
SKRAUP,  1879:  Ber.  deut.  chem.  Ges.,  12,  1107:  Jour.  Chem.  Svc.,  36,  810. 
WICHNEGRADSKY  (structure  of  cinchonine  with  both  a  quinoline  and  a  pyri- 
dine nucleus),  1881:  Bull.  S<>c.  Chim.,  [2],  34,  339;  Jour.  Chem.  Soc.,  Abs.,  444. 
DE  CONINCK,  1882-83.  KNORR  and  ANTRTCK  (positions  in  the  structure  of  quino- 
line), 1884:  Ber.  deut.  chem.  Ges..  17.  2870,  2032;  Jour.  Chem.  .Soe.,  1885,  Abs., 
273:  1884,  Abs.,  1378.  GLAUS  and  others.  Diquinolines  :  WILLIAMS,  1881, 
Chem.  News,  43,  145:  CLAUS,  1881-82;  DEWAR,  1881;  TRESSIDER,  1884;  FISCH- 
ER (and  Loo),  1  884,  1885  ;  OESTERMAYER,  1885.  KRAKAU,  1885.  BEREND,  HARTZ, 
KAHN,  SPADY,  EINHORN,  1885-86.  MICHAEL,  1885:  Am.  Chem.  Jour.,  7,  182. 
"Ladenburg's  Handworterbuch  der  Chemie,"  i.  243-298,  ii.  532-595  (63  pages 
on  quinoline).  Summaries  of  progress,  1882-85:  Am.  Chem.  Jour.,  4,  64, 
157;  5,  60,  72;  7,  200,  (182). 


COMPARATIVE   CHARACTERISTICS. 


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ioo  CINCHONA    ALKALOIDS. 

CINCHONA  ALKALOIDS,  DISTINCTIONS  between  (for  test-method^ 
conditions,  etc.,  see  under  each  alkaloid,  d) : 

I.   OF  QUININE. 

A. — From  Cinchonidine  and  Cinchonine: 

1.  Fluorescence,  in  aqueous  solutions  of  the  sulphate  and  other 

oxy-salts. 

2.  The  thalleioquin  test — with  bromine  or  chlorine  followed  by 

ammonia. 

3.  Sulphate  crystallization,    j    j^      cincllonine  more  perfectly 

4.  Solution  m  ether.  than  f         dnohonidin£ 

5.  Solution  in  ammonia. 

6.  Formation  of  herapathite,  a  crystalline  iodosulphate. 

7.  Rotatory  difference  :  from  cinchonine,  in  direction  ;  from  cin- 

chonidiiie,  in  degree. 

8.  Microchemical  examinations  (p.  101). 

B. — From  Quinidine : 

1.  Sulphate  crystallization. 

2.  Non-precipitation  by  potassium  iodide. 

3.  Non-solution  of  the  sulphate  in  chloroform. 

4.  Formation  of  herapathite. 

6.  Rotatory  difference,  in  direction. 

II.    OF  CINCHONIDINE. 
A. — From  Quinine  (I.  A,  1,  2). 
B. — From  Cinchonine: 

1.  Tartrate  precipitation. 

2.  Chloroformic  solution  of  sulphate. 

3.  Rotatory  difference,  in  direction. 

4.  Greater  solubility  in  alcohol  and  in  ether. 

C. — From  Quinidine: 

1.  Tartrate  precipitation. 

2.  Non-precipitation  by  iodide. 

3.  Non-solution  of  sulphate  in  chloroform. 

4.  Rotatory  difference,  in  direction. 

III.  OF  AMORPHOUS  ALKALOIDS. 

A. — From  the  crystallizafole  alkaloids: 

1.  By  non-crystallization  of   the  sulphate,  and  other  salts,  and 
the  free  alkaloid,  under  ordinary  or  microscopic  observation. 

B. — From  Cinchonine : 
1.  By  greater  solubility  in  ether,  or  in  dilute  alcohol. 


MICROCHEMICAL  DISTINCTIONS.  101 

Microchemical  distinctions  between  cinchona  alkaloids.— 
SCHRAGE  (1874  and  1879),  GODEFFKOY  and  LEDERMANN  (1877), 
and  HESSE  (1878)  have  made  contributions  respecting  distinc- 
tions drawn  from  the  crystals  formed  under  the  microscope 
after  adding  potassium  sulphocyanate  solution.1  GodefFroy 
and  L.  used  saturated  solutions  of  sulphates  of  the  several  alka- 
loids. Schrage  used  a  solution  of  the  alkaloidal  salt  in  100  parts 
of  water,  converting  the  sulphate  of  quinine  into  hydrochloride 
for  the  purpose.  But  Hesse  advises  to  ,use  only  saturated  solu- 
tions of  the  alkaloid  sulphates,  prepared  by  dissolving  in  warm 
water  and  leaving  in  the  cold  till  crystallization  stops.  Such 
a  solution,  by  itself,  should  not  exhibit  crystals  under  the  micro- 
scope. The  sulphocyanate  solution  should  be  very  concentrated, 
1  part  of  the  salt  to  1  part  of  water.  A  drop  of  the  alkaloid 
sulphate  solution  is  placed  on  a  glass  slide,  and  a  drop  (Hesse), 
or  a  third  to  a  fourth  of  drop  (Schrage),  of  the  reagent  is  placed 
on  one  side  of  the  alkaloid  solution,  a  cover-glass  is  put  over, 
and  the  slide  is  placed,  in  level,  under  a  power  of  about  110 
diameters.  With  Schrage's  proportions  the  crystal  forms  were 
completed  in  from  a  half-hour  to  several  hours  ;  with  Hesse's 
proportions,  in  a  few  minutes  to  half  an  hour.  In  first  contact 
with  the  reagent  amorphous  precipitation  frequently  occurs, 
followed  by  crystallization.  The  authors  above  cited  differ  from 
each  other  in  certain  important  particulars.  Thus,  with  quinine, 
Godeffroy  and  Ledermann  assert  that  the  sulphocyanate,  so  far 
as  formed,  is  in  amorphous  globules  as  a  final  form,  and  that  any 
stellate  groups  of  crystals  are  those  of  unchanged  quinine  sul- 
phate. Schrage,  later,  states  that  the  amorphous  globules  are 
resolved  into  stellate  clusters  of  crystals.  And  Hesse  states  that 
Godeffroy's  appearances,  with  quinine,  were  due  to  presence  of 
cinchonidine. 

The  analyst  who  would  undertake  the  identification  of  impu- 
rities in  cinchona  alkaloids  by  the  sulphocyanate  reaction,  or 
other  test,  in  crystalline  forms  under  the  microscope,  shouH 
govern  his  conclusions  by  the  results  of  strictly  parallel  tests, 
made  at  the  same  time  with  alkaloids  of  known  purity.  The 
concentration  of  the  alkaloidal  salt  solution  and  of  the  reagent, 
and  the  proportion  of  the  one  liquid  to  the  other,  must  be  held 


,  Archiv    d.  Phar.,  [3],  5,  504:  13,  25;  Pro.  Am.  Pharm.,  23, 
409;  27,  488.    GODEFFROY  and  L.,  Archiv  d.  Phar.,  .[31,  ii,  515:  New  Remedies, 


7,  107  (April,  1878);  Am.  Jour.  Phar.,  50,  158;  Pro.  Am.  Pharm.,  26,  569. 
0.  HESSE,  Archiv  d.  Phar.,  [3],  13,  481 ;  Pr<>.  Am.  Pharm.,  27,  492.  The  pub- 
lications above  cited  are  illustrated  with  cuts.  On  the  Identification  of  Alka- 
loids in  general  by  Crystallization  under  the  Microscope,  a  full  report  is  made 
by  A.  PERCY  SMITH,  1886:  Analyst,  u,  81  (illustrated). 


102  CINCHONA   ALKALOIDS. 

without  variation,  and  the  disturbing  influence  of  evaporation 
must  be  prevented  by  the  cover-glass  at  once.  It  is  not  prudent 
to  base  conclusions  upon  a  resemblance  to  forms  figured  by  other 
operators.  Even  slight  differences  in  the  purity  of  the  reagent 
or  in  the  atmospheric  temperature  may  cause  differences  in  the 
form  or  the  rate  of  crystallization. — The  quinidine  sulphocya- 
nate  crystals  are  more  characteristic  than  those  of  the  other  alka- 
loids, and  the  reaction  with  potassium  iodide  is  likewise  a  favor- 
able one  for  microscopic  recognition  of  quinidine. 

SEPARATION  AND  ESTIMATION  OF  CINCHONA  ALKALOIDS. — Se- 
paration of  the  total  Alkaloids  from  Cinchona  Barks. — Cin- 
chona alkaloids  exist  in  the  barks  in  combination  with  the  tannin 
— known  as  cinchotannic  acid  (DE  YRLJ,  1878).  Kinic  (quinic) 
i  acid  is  also  present  in  the  bark,  and,  under  action  of  certain 
solvents,  unites  with  a  part  of  the  alkaloids.  The  cinchotan nates 
of  the  alkaloids  are  almost  insoluble,  while  the  kinates  are  solu- 
ble, in  cold  water.  Acidulated  water  readily  dissolves  the  en- 
tire alkaloids. 

In  methods  of  analysis,  with  a  few  exceptions,  the  alkaloids 
are  liberated  by  lime  or  other  alkali,  and  dissolved  from  the 
powdered  bark,  in  a  free  state,  by  alcohol,  ether,  or  other  solvent 
of  the  free  alkaloids.  But  a  removal  of  the  alkaloids  as  hydro- 
chlorides  is  sometimes  resorted  to.  The  most  favorable  opera- 
tions for  removal  of  the  alkaloids  from  the  bark  may  be  clas- 
sified as  follows  : 

1.  The  powdered  bark  is  macerated  in  a  mixture  of  chloro- 
form or  ether,  with  alcohol  and  ammonia,  and   an  aliquot  part 
of  the  total  liquid  is  taken   (without  washing)  for  the  analysis 
(PROLLIUS,  1882;  DE  YRIJ,  1882;  Ph.  Germ.) 

2.  The  powder  mixed  with  lime  is  exhausted  with  ether  in  an 
extraction  apparatus,  Tollens's  or  other. 

3.  The  powder  mixed  with  lime  is  exhausted  by  digesting 
with  a  mixture  of  amyl  alcohol  and  ether  (SQUIBB,  1882),  or  amyl 
alcohol  and  benzene  (Br.  Phar.,  1885). 

4.  The  powder  mixed  with  lime  is  exhausted  by  digesting 
and  washing  with  alcohol  (DE  VRIJ,  1873;  U.   S.  Ph.,   1880, 
p.  78). 

5.  The  acidulous  decoction,  in  a  part  of  the  filtrate  taken  as 
a  fraction  of  the  total  solution,  is  precipitated  by  picric  acid,  and 
the  dried  precipitate  weighed  (HAGER,  1869 ;  given  in  this  work 
under  Alkaloids,  p.  49). 

The  use  of  an  extraction  apparatus,  best  adapted  to  ether  as  a 


SEPARATION  AND  ESTIMATION.  103 

solvent,  is  a  most  rigidly  exact  and  generally  satisfactory  way  in 
this  as  in  most  solvent  operations  upon  plants.  But  it  loads  the 
solution  with  more  coloring  and  other  extraneous  matters,  and 
takes  longer,  than  the  method  placed  first  above.  An  aliquot 
part  of  the  liquid,  taken  with  due  precautions,  gives  the  operator 
quick  and  trustworthy  results,  and  for  ordinary  uses  this  plan  is 
here  given  the  preference.  Other  operators  prefer  percolation 
or  hot  digestion,  or  both.  The  plans  above  enumerated  have 
been  carried  out,  in  many  cases  with  separation  of  the  alkaloids 
from  each  other,  or  of  the  quinine  from  the  other  alkaloids,  by 
different  chemists,  as  follows  : 

1.  Methods  on  the  Plan  of  Prollius.1 — The  directions  of  the 
German  Pharmacopoeia  of  1882  are  in  effect  as  follows:  Pre- 

1  PROLLIUS,  1881:  Arch.  d.  Phar.,  209,  85,  572;  Am.  Jour.  Phar.,  54,  59; 
New  Bern.,  u,  22.  J.  BIEL,  1882:  Phar.  Zeitschr.  Ruxsland,  21,  250.  DE 
VEIJ,  1882:  Jour,  de  Phar.  et  de  Chim.;  New  Item.,  n,  258;  Am.  Jour.  Phar., 
54,  59.  KISSEL,  1882:  Arch.  d.  Phar.,  220,  120.  Ph.  Germ.,  1882,  63.  FLUCK- 
IGEE,  1883:  Phar.  Zeit.t  vol.  28  ;  New  Item.,  12,  274.  A.  PETTIT,  1884.  Ci- 
tations from  above-named  authorities':  Zeit.  anal.  Ghem.,  22,  132;  Proc.  Am. 
Pharm.,  30,  204;  31,  133,  134. 

Prollius  proposed  the  ethereal  solvent  mixture  (making  it  by  weight  of  ether 
88  per  cent.,  of  ammonia-water  4  per  cent.,  of  92  to  96  per  cent  alcohol  8  per 
cent.)  for  assays  of  the  ether-soluble  alkaloids  only,  and  directed  a  chloroform 
mixture  for  assays  of  the  total  cinchona  alkaloids.  But  Biel,  and  Kissel,  and 
De  Vrij  agree  in  the  statement  that  Prollius's  ethereal  solvent  removes  all  the 
alkaloids.  Prollius,  however,  used  only  half  as  much  of  the  solvent  as  is  here 
directed,  according  to  De  Vrij.  De  Vrij  emphasizes  the  required  fineness  of 
the  powder.  He  would  prefer  a  less  aqueous  solvent,  made  by  saturating  the 
alcohol  with  ammonia,  and  adding  the  ether.  Biel  says  the  time  of  maceration 
should  be  four  hours,  neither  more  nor  less,  while  DeVrij  found  one  hour 
enough  as  shown  by  control  experiment.  Kissel  obtains  the  quantity  of  the  pure 
alkaloids  by  subtracting  from  the  quantity  of  crude  alkaloid  the  weight  of 
resins,  wax,  etc.,  left  on  a  tared  filter,  in  filtration  of  a  solution  of  the  crude 
alkaloidal  residue  in  diluted  sulphuric  acid. — The  chloroformic  solvent  of  Prol- 
lius, above  referred  to,  consisted  of  76  percent,  alcohol,  20  percent,  chloroform, 
and  4  per  cent,  ammonia-water.  The  solution  was  wine-red,  and  to  decolorize 
it  a  quantity  of  finely  powdered  calcium  hydrate  equal  to  the  quantity  of  the 
bark  is  agitated  with  the  decanted  solution,  which  is  then  filtered,  and  this  fil- 
trate is  weighed  to  obtain  an  aliquot  part,  of  the  entire  solvent  taken.  The 
weighed  filtrate  is  evaporated,  and  the  dried  residue  weighed  as  total  alkaloid, 
not  purified  further.— Tn  the  use  of  the  ethereal  solvent  Prollius  decanted  the 
clear  solution  (as  in  the  directions  above),  and  then  supersaturated  the  ethereal 
solution  with  diluted  sulphuric  acid,  when  the  alkaloidal  salts  were  found  in  a 
dense  aqueous  layer.  The  ethereal  layer  was  removed  and  washed,  once  with 
2  c.c.,  then  with'l  c.c.  of  water,  the  washings  being  added  to  the  alkaloid  solu- 
tion. From  the  latter  the  alcohol  is  evaporated,  when  ammonia  is  added  just 
to  alkaline  reaction,  and  the  precipitate  dried  in  a  tared  capsule  and  weighed. — 
The  ethereal  solution,  if  not  distilled,  should  be  evaporated  in  a  flask  or  beaker 
of  some  depth  to  avoid  creeping. — The  purification  of  the  crude  alkaloids  is  a 
matter  distinct  from  the  removal  from  the  bark,  and  may  be  varied  at  will  of 
the  operator.  The  separation  by  shaking  out  with  chloroform  (p.  33)  will  gene- 
rally be  preferred  to  precipitation  by  the  Ph  Germ. 


104  CINCHONA   ALKALOIDS. 

pare  the  solvent  mixture  by  taking  together  85  parts  by  weight 
of  ether  (s.g.  0.724  to  0.728),  10  parts  of  alcohol  (0.830  to  0.834), 
and  5  parts  of  ammonia-water  (s.g.  0.960),  making  100  parts  by 
weight. — Treat  20  grams  of  the  powdered  cinchona  with  200 
grams  of  the  solvent  mixture,  agitating  thoroughly  and  repeat- 
edly, macerate  one  day,  and  pour  off  120  grams  of  the  clear 
liquid. — Add  30  c.c.  of  decinormal '  solution  of  hydrochloric 
acid,  remove  the  ether  and  alcohol  by  distillation  or  evaporation, 
concentrating  the  volume  to  30  c.c.,  and,  if  necessary,  add  more 
hydrochloric  acid  until  the  solution  has  an  acid  reaction.  Then 
filter,  and  when  cold  add  3.5  c.c.  of  normal  solution  of  potassa. 
After  the  alkaloids  have  separated  add  to  the  clear  supernatent 
liquid  enough  potassa  solution  to  complete  the  precipitation. 
Collect  the  whole  precipitate  upon  a  filter,  and  wash  with  small 
portions  of  water,  successively  poured  on,  until  drops  of  the 
washings,  when  allowed  to  glide  over  the  surface  of  a  cold-satu- 
rated aqueous  solution  of  quinine  sulphate,  no  longer  produce  a 
cloudiness.  After  allowing  the  alkaloids  to  drain  press  them 
gently  between  bibulous  papers,  and  dry  them  by  exposure  to 
the  air  until  they  can  be  perfectly  removed  to  a  glass  capsule. 
Then  dry  them  over  sulphuric  acid,  and  finally  to  a  constant 
weight  on  the  water-bath. — Of  200  grams  total  liquid,  120  grams 
were  decanted,  and  3:5::  weight  obtained  :  #=  weight  of 
mixed  alkaloids  in  the  20  grams  of  bark.  Then  a?x5—  per  cent, 
of  alkaloids  in  the  bark. 

Directions  in  detail  for  precautions  against  error,  contri- 
buted by  De  Vrij  and  others  fur  the  method  of  Prollius,  are 
presented  as  follows  (observe  last  two  foot-notes)  :  The  bark  is  to 
be  very  finely  powdered.  If  of  over  4$  total  alkaloids,  take  10 
grams,  otherwise  20  grams  for  an  assay.  Place  the  weighed 
portion  of  the  powdered  bark  in  a  glass-stoppered  bottle  pre- 
viously tared,  add  of  the  ethereal  solvent  (above)  20  times  the 
weight  of  the  powder,  take  the  exact  total  weight  of  bottle  and 
contents,  and  agitate  from  time  to  time  for  four  hours  (BiEL.  One 
hour,  DE  VRIJ.  One  day,  Ph.  Germ.)  If  any  loss  of  weight  is 
found,  add  of  the  solvent  to  restore  it,  and  agitate  and  weigh  again. 
Decant  carefully  so  much  of  the  solution  as  can  be  obtained  per- 
fectly  clear  (into  a  flask  from  which  ether  can  be  distilled),  and 
by  weighing  the  stoppered  bottle  find  the  exact  weight  of  the 
decanted  liquid.  Distil  (or  evaporate)  off  the  ether — avoiding 

1  The  Ph.  Germ,  directs  to  add  3  c.c.  of  normal  solution  of  hydrochloric 
acid.  Fliickiger,  finding  the  resulting  volume  of  liquid  too  small  for  the  filtra- 
tion, advised  the  30  c.c.  of  decinormal  solution.  Also  advised  the  concentra- 
tion to  a  definite  volume  of  30  c.c.,  not  in  the  official  directions. 


SEPARA  TION  AND  ESTIMA  TION.  105 

its  taking  fire — then  transfer  the  residual  liquid  to  a  small  cap- 
sule tared  with  a  short  glass  rod  (rinsing  with  a  little  of  the  sol- 
vent), and  evaporate  and  dry  the  residue  on  the  water-bath. 
"Weight  of  alkaloidal  solution  decanted  from  the  bottle  :  weight 
of  total  solvent  taken  in  the  bottle  : :  weight  of  residue  :  x  = 
quantity  of  crude  alkaloids  in  the  amount  of  bark  taken. — To 
obtain  the  pure  alkaloids,  the  residue  of  the  crude  alkaloids  is 
dissolved  in  diluted  hydrochloric  acid,  the  solution  filtered  and 
the  filter  washed,  the  filtrate  made  alkaline  with  sodium  hydrate 
and  repeatedly  shaken  out  with  chloroform,  the  chloroi'ormic 
solution  evaporated  (or  distilled)  in  a  tared  dish,  and  the  residue 
dried  at  100°  C.  and  weighed.  De  Yrij  found  the  pure  alkaloids 
so  obtained  to  be  16.5$  less  than  the  crude  in  the  case  of  a  red 
Java  bark. 

2.  Removal  of  the  Alkaloids  from  the  Bark  ~by  use  of  an 
Extraction  Apparatus. — For  the  use  of  an  extraction  apparatus 
upon  cinchona  bark,  with  ether  as  a  solvent,  the  following  ex- 
cellent directions  of  Professor  FLUCKIGER  are  given  : 1  Of  a  well- 
selected  average  specimen  of  the  bark  20  grains  are  very  finely 
powdered,  moistened  with  ammonia-water,  and,  after  standing 
for  an  hour,  mixed  with  80  grams  of  hot  water ;  it  is  then  al- 
lowed to  cool,  subsequently  mixed  with  milk  of  lime  (prepared 
by  triturating  5  grams  of  dry  caustic  lime  with  50  grams  of 
water),  and  the  mixture  evaporated  on  a  water-bath  until  it  is 
uniformly  converted  into  small,  somewhat  moist,  crumb  like  par- 
ticles, this  is  then  transferred  to  a  cylindrical  glass  tube  about 
2.5  centimeters  (1  inch)  wide  and  16  centimeters  (6.4  inches) 
long,  the  tube  being  fitted  as  the  percolator  of  an  extraction 
apparatus.  The  neck  of  this  percolator  is  fitted  with  a  rest  of 
wire  cloth,  on  which  a  disk  of  filtering-paper  is  held  by  a  loose 
plug  of  cotton.  The  powder  is  packed  quite  compactly,  and 
covered,  at  the  top,  with  a  plug  of  cotton  which  has  been  used 
to  clean  away  the  last  traces  of  the  bark.  The  percolator  is 
put  in  place,  under  a  condenser,  in  the  extraction  apparatus, 
into  the  receiver  of  which  about  100  c.c.  of  ether  is  introduced, 
and  the  extraction  is  conducted,  in  the  usual  manner,  over  a 
water-bath  for  nearly  a  day,  and  until  completed  as  shown  by 
testing  a  little  of  the  percolate.  This  may  be  tested,  in  the 

1  "  The  Cinchona  Barks,"  Power's  translation,  Phila.,  1884,  p.  69.  Other 
solvents  have  been  used  on  cinchona  with  an  extraction  apparatus.  Chloroform 
is  used  in  Carles's  process  (1 873 :  Zeitsch.  anal.  Chem. ,  9,  497).  Methylated  Ether, 
and  doubtless  alcohol  or  Methylated  Alcohol,  can  be  well  used  in  a  form  of  ex- 
traction apparatus  that  would  carry  over  the  vapor  with  desirable  rapidity. 


io6  CINCHONA   ALKALOIDS. 

ethereal  solution,  by  about  an  equal  volume  of  potassium  mer- 
curic iodide  solution.1 

When  the  extraction  is  completed,  36  c.c.  of  decinormal 
solution  of  hydrochloric  acid  (3.64  grams  in  1  liter)  are  added 
to  the  ethereal  solution  in  the  receiver,  when  the  ether  is  distilled 
off,  and  enough  hydrochloric  acid  then  added  to  give  an  acid 
reaction.  When  cold  the  liquid  is  filtered,  the  filter  washed, 
and  40  c.c.  of  decinormal  solution  of  soda  (4  grams  in  1  liter)  are 
added.  The  precipitate  is  left  at  rest  till  the  liquid  above  it  is 
clear.  Sodium  hydrate  solution  (preferably  of  spec.  grav.  1.3)  is 
then  added  to  complete  the  precipitation,  the  precipitate  is  col- 
lected on  a  filter,  and  gradually  washed  with  a  little  cold  water 
until  a  few  drops  of  the  washings,  when  allowed  to  flow  on  the 
surface  of  a  cold-saturated  neutral  aqueous  solution  of  quinine 
sulphate,  cease  to  produce  a  turbidity.  The  drained  precipitate 
contained  on  the  filter  is  then  gently  pressed  between  bibulous 
paper,  and  dried  by  exposure  to  the  air.  It  may  afterward 
be  readily  removed  from  the  paper  without  loss,  and,  after  tho- 
rough drying  upon  a  watch-glass  over  sulphuric  acid,  is  finally, 
dried  at  100°  C.  and  weighed.  The  weight  of  the  precipitate, 
multiplied  by  5,  will  give  the  total  percentage  of  mixed  alkaloids 
in  the  bark. 

3.  The  use  of  ethereal  or  ~benzolated  mixture  ofAmyl  Alcohol 
to  dissolve  the  free  cinchona  alkaloids,  which  are  then  trans- 
ferred to  aqueous  solution  of  the  salts  of  these  alkaloids. — A. — 
Squibtfs  Process : 5  "  Take  of  the  powdered  cinchona  5  ^rams ; 
lime,  well  burnt,  1.25  grams;  amyl  alcohol,  stronger  ether,  puri- 
fied chloroform,  normal  solution  of  oxalic  acid,  normal  solution 
of  soda,  and  water,  each  a  sufficient  quantity — or  double  all  the 
quantities  throughout,  as  well  as  the  size  of  the  vessels,  etc.,  if 

1  The  ethereal  solution  may  be  treated  according  to  the  following  direc- 
tions of  FLUCKIGEU,  or  by  any  desired  method  for  purifying  the  alkaloids  from 
resins,  etc. 

2E.  R.  SQUIBB,  1882:  EpTiemeris,  i,  106;  BR.  PH.,  1885,  111. 

Squibb  digests  first  with  amyl  alcohol  alone,  then  adds  ether  in  larger 
volume  "to  facilitate  percolation  and  evaporation."  The  Br.  Ph.  digests  with 
a  mixture  of  amyl  alcohol  with  thrice  its  volume  of  benzene.  Squibb  takes  the 
alkaloids  out  of  the  amylic  liquid  by  aqueous  oxalic  acid;  theBr.  Ph.,  by  aqueous 
hydrochloric  acid.  Squibb  purifies  the  total  free  alkaloids  by  shaking  out  with 
chloroform  in  alkaline  mixture.  The  Br.  Ph.  undertakes  the  separation  of  the 
quinine  with  cinchonidine  by  precipitation  as  tartrates.  then  precipitating  the 
remainder  of  the  alkaloids  from  the  filtrate  as  free  alkaloids,  these  separations 
serving  also  to  purify.  The  method  of  Dr.  Squibb,  in  his  unrivalled  explicitness 
of  detail,  provides  with  great  care  against  inefficient  treatment.  The  approxi- 
mate separation  with  tartrate  by  the  Br.  Ph.  corresponds  very  nearly  to  Squibb's 
approximate  division  into  ether-soluble  and  ether-insoluble  alkaloids,  p.  117. 


SEPARATION  AND  ESTIMATION.  107 

the  barks  be  poor,  or  if  it  be  desired  to  divide  the  errors  of  mani- 
pulation. 

"Add  to.  the  lime  contained  in  a  10  c.m.  =  4-inch  capsule 
30  c.c.  of  hot  water,  and  when  the  lime  is  slaked  stir  the  mix- 
ture and  add  the  powdered  cinchona,  stir  very  thoroughly,  and 
digest  in  a  warm  place  for  a  few  hours  or  over  night.  Then  dry 
the  mixture  at  a  low  temperature  on  a  water-bath,  rub  it  to  powder 
in  the  capsule,  and  transfer  it  to  a  flask  of  100  c.c.  capacity  and 
add  to  it  25  c.c.  of  amyl  alcohol.  Cork  the  flask  and  digest  in  a 
water-bath  at  a  boiling  temperature  and  with  vigorous  shaking 
for  four  hours.  Then  cool  and  add  60  c.c.  of  stronger  ether,  of 
sp.  gr.  0.728,  and  again  shake  vigorously  and  frequently  during 
an  hour  or  more.  Filter  off  the  liquid  through  a  double  filter  of 
10  c.m.  =  4  inches  diameter  into  a  flask  of  150  c.c.  capacity,  and 
transfer  the  residue  to  the  filter.  Rinse  out  the  flask  on  to  the 
filter  with  a  mixture  of  10  volumes  of  amyl  alcohol  and  40  of 
stronger  ether,  and  then  percolate  the  residue  on  the  filter  with 
15  c.c.  of  the  same  mixture  added  drop  by  drop  from  a  pipette 
to  the  edges  of  the  filter  and  surface  of  the  residue.  Return  the 
residue  to  the  flask  from  whence  it  came,  add  30  c.c.  of  the  amyl 
alcohol  and  ether  mixture,  shake  vigorously  for  five  minutes  or 
more,  and  return  the  whole  to  the  filter.  Again  percolate  the 
residue  with  15  c.c.  of  the  menstruum  applied  drop  by  drop 
from  a  pipette  as  before.  Then  put  the  filter  and  residue  aside, 
that  it  may  be  afterward  tested  in  regard  to  the  degree  of  ex- 
haustion. 

"  Boil  off  the  ether  from  the  filtrate  in  the  flask  by  means  of 
a  water-bath,  taking  great  care  to  avoid  igniting  the  ether  vapor, 
and  also  to  avoid  explosive  boiling,  by  having  a  long  wire  in 
the  flask.  When  boiled  down  as  far  as  practicable  in  the 
flask  transfer  the  remainder  to  a  tared  capsule  of  10  c.m.  =  4 
inches  diameter,  and  continue  the  evaporation  on  a  water-bath 
until  the  contents  are  reduced  to  about  6  grams.1  Transfer 
this  to  a  flask  of  100  c.c.  capacity,  rinsing  the  capsule  into  the 
flask  with  not  more  than  4  c.c.  of  amyl  alcohol.  Then  add  6  c.c. 
of  water  and  4  c.c.  of  normal  solution  of  oxalic  acid,  and  shake 
vigorously  and  frequently  during  half  an  hour.  Pour  the  mix- 
ture while  intimately  mixed  on  to  a  well-wetted  double  filter  of 
12  c.m.  —4}  inches  diameter,  and  filter  off  the  watery  solution 
from  the  amyl  alcohol  into  a  tared  capsule  of  10  c.m.  —  4  inches 

1  If  only  a  very  rough  estimate  of  the  total  alkaloids  be  needed,  this  may 
be  obtained  by  continuing  the  evaporation  of  the  amyl  alcohol  solution  to  a 
constant  weight,  and  subtracting  from  the  result  a  half  of  1  per  cent,  of  the 
•weight  of  bark  uiken  (SQUIBB). 


io8  CINCHONA   ALKALOIDS. 

diameter.  Wash  the  filter  and  contents  with  5  c.c.  of  water  ap- 
plied drop  by  drop  from  a  pipette  to  the  edges  of  the  filter  and 
surface  of  the  amyl  alcohol.  Then  pour  the  amyl  alcohol  back 
into  the  flask  over  the  edge  of  the  filter  and  funnel,  rinsing  the 
last  portion  in  with  a  few  drops  of  water.  Add  10  c.c.  of  water 
and  1  c.c.  of  normal  solution  of  oxalic  acid;  again  shake  vigo- 
rously for  a  minute  or  two,  and  return  the  whole  to  the  wetted 
filter  and  filter  off  the  watery  portion  into  the  caps  ale  with  the 
first  portion.  Return  the  amyl  alcohol  again  to  the  flask,  and 
repeat  the  washing  with  the  same  quantities  of  water  and  normal 
oxalic  acid  solution.  When  this  lias  drained  through,  wash  the 
filter  and  contents  with  5  c.c.  of  water  applied  drop  by  drop  from 
a  pipette.  Evaporate  the  total  filtrate  in  the  capsule  on  a  water- 
bath  at  a  low  temperature  until  it  is  reduced  to  about  15  grams, 
and  return  this  to  a  flask  of  100  c.c.  capacity,  rinsing  the  cap- 
sule into  the  flask  with  5  c.c.  of  water.  Add  20  c.c.  of  puri- 
fied chloroform,  and  then  6.1  c.c.  of  normal  solution  of  soda, 
and  shake  vigorously  for  five  minutes  or  more.  While  still  inti- 
mately mixed  by  the  shaking  pour  the  mixture  upon  a  filter  12 
c.m.  =  4f  inches  diameter,  well  wetted  with  water.  When  the 
watery  solution  has  passed  through,  leaving  the  chloroform  on 
the  filter,  wash  the  filter  and  chloroform  with  5  c.c.  of  water 
applied  drop  by  drop.  Then  transfer  the  chloroform  solution,  by 
making  a  pin-hole  in  the  point  of  the  filter,  to  another  filter  of 
10  c,m.  =  4  inches  diameter,  well  wetted  with  chloroform,  and 
placed  over  a  tared  flask  of  1 00  c.c.  capacity.  Wash  the  watery 
filter  through  into  the  chloroform- wet  filter  with  5  c.c.  of  the 
purified  chloroform,  and,  when  this  has  passed  through  into  the 
flask,  wash  the  chloroform-wet  filter  also  with  5  c.c.  of  chloro- 
form applied  drop  by  drop  to  the  edges  of  the  filter.  When  the 
whole  chloroform  solution  of  alkaloids  is  collected  in  the  flaskt 
boil  off  the  chloroform  to  dryness  in  a  water-bath,  when  the  alka- 
loids will  be  left  in  warty  groups  of  radiating  crystals  adhering 
over  the  bottom  and  sides  of  the  flask.  Place  the  flask  on  its 
side  in  a  drying-stove,  and  dry  at  100°  C.  to  a  constant  weight. 
The  weight  of  the  contents  multiplied  by  20  gives  the  percentage 
of  the  total  alkaloids  of  the  cinchona  in  an  anhydrous  condition, 
to  within  0.1  or  0.2  of  a  per  cent,  if  the  process  has  been  well 
managed." 

B. — J3r.  Ph.  Process. — (1)  For  Quinine  and  Cinchonidine : 
"  Mix  200  grains  [or  12.5  grams]  of  the  (red)  cinchona  bark,  in 

1  For  an  "  Estimation  of  the  Quinine,"  as  represented  by  an  ether-soluble 
division  of  the  alkaloids,  following  the  above  method,  by  the  same  author, 
see  p.  117. 


SEPARATION  AND  ESTIMATION.  109 

No.  60  powder,  with  60  grains  [or  4  grams]  of  hydrate  of  cal- 
cium ;  slightly  moisten  the  powder  with  \  oz.  [14  c.c.]  of  water; 
mix  the  whole  intimately  in  a  small  porcelain  dish  or  mortar ; 
allow  the  mixture  to  stand  for  an  hour  or  two,  when  it  will 
present  the  characters  of  a  moist,  dark-brown  powder,  in  which 
there  should  be  no  lumps  or  visible  white  particles.  Transfer 
this  powder  to  a  six-ounce  flask  [one  of  about  170  c.c.  capacity], 
add  3  fluid  ounces  [85  c  c.]  of  benzolated  amyl  alcohol  [amyl 
alcohol,  1  volume ;  benzene  of  sp.  gr.  about  0.850,  3  vols.],  boil 
them  together  for  about  half  an  hour,  decant  and  drain  off  the 
liquid  on  to  a  filter,  leaving  the  powder  in  the  flask ;  add  more 
of  the  benzolated  amyl  alcohol  to  the  powder,  and  boil  and  de- 
cant as  before  ;  repeat  this  operation  a  third  time  ;  then  turn  the 
contents  of  the  flask  on  to  the  filter,  and  wash  by  percolation 
with  the  benzolated  amyl  alcohol  until  the  bark  is  exhausted. 
If  during  the  boiling  a  funnel  be  placed  in  the  mouth  of  the 
flask,  and  another  flask  filled  with  cold  water  be  placed  in  the 
funnel,  this  will  form  a  convenient  condenser  which  will  prevent 
the  loss  of  more  than  a  small  quantity  of  the  boiling  liquid. 
Introduce  the  collected  filtrate,  while  still  warm,  into  a  stoppered 
glass  separator ;  add  to  it  20  minims  [1.1  c.c.]  of  diluted  hydro- 
chloric acid  [of  10.58$  real  acid]  mixed  with  2  fluid-drachms 
[7  c.c.]  of  water;  shake  them  well  together,  and  when  the  acid 
liquid  has  separated  this  may  be  drawn  off,  and  the  process 
repeated  with  distilled  water  slightly  acidulated  with  hydrochlo- 
ric acid,  until  the  whole  of  the  alkaloids  have  been  removed. 
The  acid  liquid  thus  obtained  will  contain  the  alkaloids  as  hy- 
drochlorates,  with  excess  of  hydrochloric  acid.  It  is  to  be  care- 
fully and  exactly  neutralized  with  ammonia  while  warm,  and 
then  concentrated 'to  the  bulk  of  3  fluid-drachms  [about  10  c.c.] 
If  now  about  15  grains  [0.972  gram]  of  tartarated  soda  [potas- 
sium sodium  normal  tartrate],  dissolved  in  twice  its  weight  of 
water,  be  added  to  the  neutral  hydrochlorates,  and  the  mixture 
stirred  with  a  glass  rod,  insoluble  tartrates  of  quinine  and  cin- 
ch onidine  will  separate  completely  in  about  an  hour ;  and  these 
collected  on  a  filter,  washed,  and  dried,  will  contain  eight-tenths 
of  their  weight  of  the  alkaloids,  quinine  and  cinchonidine,  which 
[in  grains]  divided  by  2  [or  in  grams  multiplied  by  8]  repre- 
sents the  percentage  of  those  alkaloids.  The  other  alkaloids  will 
be  left  in  the  mother-liquor." — (2)  For  total  alkaloids:  "To 
the  mother-liquor  from  the  preceding  process  add  solution  of 
ammonia  in  slight  excess.  Collect,  wash,  and  dry  the  precipi- 
tate, which  will  contain  the  other  alkaloids.  The  weight  of  this 
precipitate  [in  grains]  divided  by  2  [or,  in  use  of  the  metric 


no  CINCHONA  ALKALOIDS. 

quantities,  its  weight  ingrains  multiplied  bj  8],  and  added  to  the 
percentage  weight  of  the  quinine  and  cinchonidme,  gives  the 
percentage  of  total  alkaloids." 

4.  The  use  of  alcohol  to  dissolve  the  free  cinchona  alkaloids, 
then  obtained  by  precipitation  from  aqueous  solution? — The  di- 
rections of  the  II.  S.  Ph.  are  as  follows :  "  For  total  alkaloids : 
Cinchona,  in  No.  80  powder,  and  fully  dried  at  100°  C.,  20 
grams  ;  lime,  5  grains ;  diluted  sulphuric  acid,  solution  of  soda, 
alcohol,  distilled  water,  each  a  sufficient  quantity.  Make  the 
lime  into  a  milk  with  50  c.c.  of  distilled  water,  thoroughly  mix 
therewith  the  cinchona,  and  dry  the  mixture  completely  at  a 
temperature  not  above  80°  C.  (176°  F.)  Digest  the  dried  mix- 
ture with  200  c.c.  of  alcohol,  in  a  flask,  near  the  temperature  of 
boiling,  for  an  hour.  When  cool  pour  the  mixture  upon  a  filter 
of  about  six  inches  (15  centimeters)  diameter.  Rinse  the  flask  and 
wash  the  filter  with  200  c.c.  of  alcohol,  used  in  several  portions, 
letting  the  filter  drain  after  use  of  each  portion.  To  the  filtered 
liquid  add  enough  diluted  sulphuric  acid  to  render  the  liquid 
acid  to  test-paper.  Let  any  resulting  precipitate  (sulphate  of 
calcium)  subside ;  then  decant  the  liquid,  in  portions,  upon  a 
very  small  filter,  and  wash  the  residue  and  filter  with  small  por- 
tions of  alcohol.  Distil  or  evaporate  the  filtrate  to  expel  all  the 
alcohol,  cool,  pass  through  a  small  filter,  and  wash  the  latter  with 
distilled  water  slightly  acidulated  with  diluted  sulphuric  acid, 
until  the  washings  are  no  longer  made  turbid  by  solution  of  soda. 
[Alternative  directions,  from  this  point,  given  below. .]  To  the 
filtered  liquid,  concentrated  to  the  volume  of  about  50  c.c.,  when 
nearly  cool,  add  enough  solution  of  soda  to  render  it  strongly 
alkaline.  Collect  the  precipitate  on  a  wetted,  filter,  let  it  drain, 
and  wash  it  with  small  portions  of  distilled  water  (using  as  little 

~DE  VRIJ,  1873:  Phar.  Jour  Trans  ,  [8],  4,  241;  Proc.  Am.  Phar.,  22,  268. 
U.  S.  Ph.,  1880,  p.  78.  A.  B.  Prescott  in  "Report  on  the  Revision  of  the 
U.  S.  Ph.,"  New  York,  1880,  p.  26. 

This  is  a  direct  and  simple  method,  in  common  use  and  giving  good  results. 
The  precipitation  and  washing  is  open  to  the  objection,  elsewhere  noted,  that 
quinine  thereby  suffers  a  little  loss.  This  is  avoided  in  the  alternative  modifica- 
tion by  shaking  out  the  total  alkaloids  with  chloroform,  given  here  from  the 
"  Report  on  Revision." 

GCEBEL  (1884:  Proc.  Am.  Phar.,  32,  474)  proposes,  very  properly,  the  adap- 
tation of  the  process  to  the  plan  of  taking  an  aliquot  partot  the  alcoholic  solu- 
tion, as  in  Prollius's  method,  as  follows:  "  Place  15  grams  of  cinchona — treated 
with  milk  of  lime  and  perfectly  dried — in  a  flask,  add  150  c.c.  of  alcohol,  weigh 
the  whole,  digest  the  loosely  stoppered  flask  and  contents  for  about  two  hours 
at  150°  to  160°  F.,  cool,  replace  the  slight  loss  of  weight  by  alcohol,  filter, 
through  a  covered  filter,  100  c.c.  equivalent  to  10  grams  of  the  bark,  and 
proceed  with  this  extraction  practically  as  directed  by  the  Pharmacopoeia." 


SEPARATION  AND  ESTIMATION.  in 

as  possible)  until  the  washings  give  but  a  slight  turbidity  with 
test-solution  of  chloride  of  barium.  Drain  the  filter  by  laying  it 
upon  blotting  or  filter  papers  until  it  is  nearly  dry. 

"  Detach  the  precipitate  carefully  from  the  filter  and  transfer 
it  to  a  weighed  capsule,  wash  the  filter  with  distilled  water  aci- 
dulated with  diluted  sulphuric  acid,  make  the  filtrate  alka- 
line by  solution  of  soda,  and,  if  a  precipitate  result,  wash  it  on 
a  very  small  filter,  let  it  drain  well,  and  transfer  it  to  the  capsule. 
Dry  the  contents  of  the  latter  at  100°  C.  (212°  F.)  to  a  con- 
stant weight,  cool  it  in  a  desiccator,  and  weigh.  The  number 
of  grams  multiplied  by  five  (5)  equals  the  percentage  of  total 
alkaloids  in  the  cinchona." 

Alternative  directions  from  point  above  noted :  Concentrate 
the  filtrate  to  the  volume  of  50  c.c.  or  less.  Transfer,  rinsing 
with  a  little  water,  to  a  glass  separator  of  100  to  150  c.c.  ca- 
pacity. Add  solution  of  soda  in  decided  excess,  then  at  once 
add  30  to  40  c.c.  of  chloroform,  stopper,  agitate  for  a  few 
minutes,  set  aside  for  an  hour  or  two,  and  draw  off  the  clear 
chloroform  layer.  In  the  same  way  extract  with  three  smaller 
portions  of  the  chloroform,  using  in  all  at  least  120  to  130  c.c. 
of  this  solvent.  The  chloroform  is  then  recovered  by  distilla- 
tion or  is  slowly  evaporated,  the  concentrated  liquid  is  trans- 
ferred, with  chloroform  rinsing,  to  a  weighed  dish,  and  the  re- 
sidue dried  on  the  water-bath  to  a  constant  weight.  The  grams 
multiplied  by  5  express  the  percentage  of  total  alkaloids  in  the 
bark.1 

SEPARATION  OF  CINCHONA  ALKALOIDS  FROM  EACH  OTHER. 

I.   SEPARATION  OF  QUININE. 
A. — From  other  cinchona  alkaloids  in  general* 

1.  By  crystallization  of  the  sulphate  in  aqueous  solution  (p.  113). 

2.  "  crystallization  of  herapathite  (under  Quinine,  f,  "Hera- 

pathite  " ). 

3.  "  solution  in  ether  (p.  116). 

4.  "  solution  in  ammonia  (see    under  Quinine,  <7,  "Kerner's 

Test"). 

1  "This  I  find,"  shaking  out  with  50  c.c.  and  then  with  three  successive 
portions,  each  of  25  c.c.  of  chloroform,  "will  bring  back  invariably  5.99  out  of 
6.00  grams  of  pure  mixed  alkaloids,  and  is  decidedly  the  most  accurate  method, 
given  practice  in  the  way  of  shaking,  etc.,  so  as  to  get  the  chloroform  to  settle 
quickly."— J.  MUTER,  1880:  The  Analyst,  London,  5,  223. 

2  There  may  be  added,  for  trial,  (5)  separation  by  precipitation  as  Oxalate — • 
Shimoyama,  1885:  Archiv  d.  Phar.,  [3],  23,  209. 


112  CINCHONA  ALKALOIDS. 

B.  —  From  Cinchonidine. 

1.  By  recrystallizations  of  the  sulphate  (p.  113). 

2.  "  solution  in  ammonia,  in  filtrate  from  saturated    sulphate 

(p.  H7). 

C.  —  From  Quinidine. 

1.  By  non-precipitation  with  potassium  iodide  (see  Quinidine,  /*). 

2.  "  non-solution  of  the  sulphate  in  chloroform.1 

3.  "  precipitation  as  normal  tartrate. 

JX  —  From  Cinchonine. 

1.  By  non-solution  of  the  sulphate  in  chloroform.1 

2.  "  precipitation  as  neutral  tartrate  (compare  "  Separation  of 

Cinchonidine,"  p.  118). 

E.  —  From  Amorphous  Alkaloids. 
1.  By  crystallization  of  the  sulphate. 

II.  SEPARATION  OF  CINCHONIDINE. 

A.  —  From  other  cinchona  alkaloids  in  general. 

1.  After  removal  of  Quinine,  by  precipitation  with  normal  tar- 

trate (p.  118). 

2.  By  precipitation  as  tartrate,  followed  by  removal  from  Qui- 

nine by  I.  A.  1,  2,  3,  or  4. 

B.  —  From  Cinchonine  and  Quinidine. 

1.  By  non-solution  of  the  sulphate  in  chloroform. 

2.  "  precipitation  as  neutral  tartrate  (p.  118). 

C.  —  From  Quinine. 

1.  By  non-crystallization  as  sulphate,  repeated  (p.  113). 

2.  "  solution  in  excess  of  ammonia  after  filtration  of  sulphate 

(p. 


D.  —  From  Amorphous  Alkaloids. 
1.  By  crystallization  as  normal  tartrate  (p.  119). 

1  Taken  separately,  quinine  sulphate  and  cinchonidme  sulphate  each  re- 
quires about  1000  parts  of  chloroform  for  solution,  while  quinidine  sulphate 
dissolves  in  20  parts,  and  cinchonme  sulphate  in  60  parts,  of  this  solvent. 
Taken  in  mixtures  of  quinine  or  cinchonidine  with  quinidine  or  cinchonine, 
these  differences  of  solubility  are  seriously  diminished  (the  author  with  Mr. 
Thum,  1878:  Proc.  Am.  Pharm.,  26,  831). 


SEPARATION  OF  QUININE.  113 

III.  SEPARATION  OF  CINCHONINE. 

A.  —  From  other  cinchona  alkaloids  in  general. 

1.  By  non-solution  in  ether  (p.  116). 

2.  "  more  sparing  solution  in  alcohol. 

B.  —  From  Quinine. 

1.  By  not  crystallizing  as  sulphate  (see  below). 

2.  "  solution  of  the  sulphate  in  chloroform  (see  note  on  p.  112). 

C.  —  From  Cinchonidine. 

1.  By  solution  of  the  sulphate  in  chloroform. 

2.  "  non-precipitation  as  neutral  tartrate  (p.  119). 

D.  —  From  Quinidine. 

1.  By  non-precipitation  with  potassium  iodide  (Quinidine,  e). 

E.  —  From  Amorphous  Alkaloids. 

1.  By  dilute  alcohol. 

2.  "  ether. 

^  SEPARATION  OF  QUININE  (I.  A,  1)  from  other  cinchona  alka- 
loids in  general,  by  crystallization  of  the  sulphate  in  aqueous 
solution  —  The  solubilities  of  the  sulphates  of  the  four  alkaloids 
in  water  at  15°  C.  (59°  F.)  is,  respectively,  quinine,  740  parts; 
quinidine  and  cinchonidine,  each  100  parts  ;  cinchonine,  70 
parts.  The  comparative  insolubility  of  quinine  sulphate  in  cold 
water  is  the  most  trusty  factor  in  Kerner's  test  for  quinine,  offi- 
cial in  U.  S.  Ph.,  in  Ph.  Germ,  since  1872,  and  in  the  Ph.  Fran., 
1884.1  Sulphate  insolubility  also  enters  into  the  Br.  Ph.  test 
The  insolubility  of  quinine  sulphate  is  not  materially  affected  by 
the  presence  of  other  cinchona  alkaloidal  sulphates,2  which  is, 
unfortunately,  not  true  of  the  solubility  of  quinine  in  ether,  or  of 
the  insolubility  of  quinine  sulphate  in  chloroform. 

To  effect  complete  separations,  however,  several  recrystalliza- 
tions  are  necessary.  Cinchonidine  certainly  opposes  some  resist- 
ance to  separation  from  quinine.  HESSE  has  recently  reaffirmed  3 
that  quinine  sulphate  is  fully  freed  from  as  much  as  2  per  cent,  of 
cinchonidine  sulphate  by  two  crystallizations  from  boiling  water. 


,  1862:  Zeitsch.  anal.  Chem.,  1,  150;  Phar.  Jour.  Trans.,  [2],  4,  19; 
Am.  Jour.  Phar.,  34,  417.  1880:  Archiv  d.  Phar.,  [3],  16,  186;  17,438;  Jour. 
Chem.  Soc.,  40,  63.  Kerner  rests  the  separation  in  good  part  upon  the  action 
of  ammonia  in  the  filtrate. 

2  The  author  and  Mr.  Thum,  1878:  Proc.  Am.  Pharm.,  26,  834.     "  Report' 
on  Revision  U.  S.  Ph.,"  1880,  pp.  29,  116. 

3  HESSE,  1886:  Phar.  Jour.  Trans.,  [3],  16,  818;  (1885)  [3],  15,  869. 


114  CINCHONA   ALKALOIDS. 

DAVIES  (1885) l  found  numerous  recrystallizations  necessary  to 
obtain'  a  salt  with  constant  rotatory  power.  KEENER  (1880) a 
found  that  three  to  six  crystallizations  of  commercial  quinine  sul- 
phate suffice  to  give  a  perfectly  pure  salt,  as  shown  by  a  constant 
behavior  in  his  ammonia  titration.  KEENER  (1880)  further  states 
that  in  crystallizing  from  hot  watery  solution  a  slightly  basic 
salt  is  crystallized.  In  this  case  the  cleaned  crystals  become 
slightly  alkaline  to  test-paper,  while  the  filtrate  becomes  acidu- 
lous to  a  corresponding  degree. 

To  effect  the  utmost  separation  by  one  crystallization  it  is  in- 
dispensable to  hold  the  reaction  of  the  initial  solution  exactly 
neutral,  as  a  slight  acidity  increases  the  solubility  of  quinine  sul- 
phate. In  separations  for  estimation,  therefore,  the  reaction 
should  be  neutral  But  in  separation  to  prepare  absolutely  pure 
quinine  salt,  though  at  expense  of  partial  loss,  crystallization 
from  acidulous  solution  is  more  efficient.  DE  YRIJ  has  advised 
to  convert  to  the  definite  acid  sulphate  [by  adding  as  much  more 
sulphuric  acid  as  the  quantity  required  to  convert  the  free  alka- 
loids into  neutral  salts]  ;  then  crystallize  the  acid  salt,  recrystal- 
lizing  as  necessary ;  and  finally  form  the  normal  salt  by  precipi- 
tating one-half  as  the  hydrate,  and  dissolving  the  washed  precipi- 
tate in  solution  of  the  remaining  acid  salt. 

The  following  directions  for  separation  of  quinine  as  sul- 
phate are  in  effect  those  of  the  U.  S.  Ph.,  1880  (p.  79),3  but  with 
provision  for  better  regulation  of  the  use  of  acid  and  alkali,  an 
increase  of  temperature  in  the  digestion  before  crystallizing,  and 
the  drying  to  anhydrous  instead  of  effloresced  sulphate.  The 
unchanged  pharmacopceial  text  is  enclosed  in  quotation-marks. 

' '  To  the  total  alkaloids  from  20  grams  of  cinchona,  previously 
weighed,"  or  to  a  weighed  quantity  (0.5  to  5.0  grams)  of  any 
ordinary  mixture  of  free  cinchona  alkaloids,  taken  in  a  weighed 
beaker  of  capacity  of  about  120  fluid  parts  for  1  part  of  alka- 
loids, add  from  a  burette  decinormal  solution  of  sulphuric  acid 
until  the  liquid  is  "  just  distinctly  acid  to  litmus-paper  "  and  re- 
tains this  degree  of  acidity  after  15  to  30  minutes'  digestion  on 

1  DAVIES,  1885:  Phar.  Jour.  Trans.,  [3],  16,  358.  To  same  effect,  OUDE- 
MANS,  Jahr.  Chem.,  1876.  It  is  surmised  that  a  double  sulphate  of  cinclioni- 
dine  and  quinine  crystallizes,  according  to  KOPPESCHAAR  (1885)  with  6H20. 
See,  also,  YUNGFLEISCH,  1887:  Phar.  Jour.  Trans.  [3]  17,  585 

2KERNER,  1880:  Archiv  d.  Phar.,  [3],  16,  191.  As  to  the  ammonia  test, 
see  under  Quinine,  g,  "Kerner's  test."  Kerner  found  that  heating  the  solution 
before  the  crystallizing  at  15°  C.  had  little  influence  on  the  result. 

3 Given  first  in  the  author's  contribution  to  "Report  on  Revision  U.  S. 
Ph.,"  1880,  p.  26.  Data  taken  from  the  report  of  Prescott  and  Thum,  1878: 
Proc.  Am.  Pharm.,  26,  834. 


SEPARATION  OF  QUININE.  115 

the  water-bath.1  Add  now  decinormal  solution  of  soda  from  the 
burette  until  after  stirring  the  reaction  is  "  exactly  neutral  to  the 
test-paper."  Note  the  number  of  c.c.  of  acid  and  of  alkali 
which  have  been  added.2  Add  water  "  to  make  the  whole  weigh 
seventy  times 3  the  weight  of  the  alkaloids."  Heat  to  near  boil- 
ing for  five  or  ten  minutes,  "  then  cool  to  15°  C.  (59°  F.)  and 
maintain  at  this  temperature  for  half  an  hour.  If  crystals  do  not 
appear  the  total  alkaloids  do  not  contain  quinine  in  quantity  over 
eight  per  cent,  of  their  weight  (corresponding  to  nine  per  cent, 
of  sulphate  of  quinine,  crystallized).  If  crystals  appear  in  the 
liquid  pass  the  latter  through  a  filter  not  larger  than  necessary, 
prepared  by  drying  two  filter-papers  of  two  to  three  and  a  half 
inches  (5  to  9  centimeters)  diameter,  trimming  them  to  an  equal 
weight,  folding  them  separately,  and  placing  one  within  the 
other  so  as  to  make  a  plain  filter  fourfold  on  each  side.  When 
the  liquid  has  drained  away  wash  the  filter  and  contents  with 
distilled  water  of  a  temperature  of  15°  C.  (59°  F.),  added  in 
small  portions,  until  the  entire  filtered  liquid  weighs  ninety 
times4  the  weight  of  the  alkaloids  taken.  Dry  the  filter,  with- 
out separating  its  folds,"  at  100°  C.,5  "  to  a  constant  weight,  cool, 
and  weigh  the  inner  filter  and  contents,  taking  the  outer  filter  for 
a  counter  weight.  To  the  weight  of"  anhydrous  sulphate  of 
quinine  so  obtained  add  16.89  per  cent,  of  its  amount  for  water 
of  crystallization.6  "And  add  0.12  percent,  of  the  weight7  of 

JIf  the  alkaloids  be  contaminated  with  resin  and  kinic  acid,  add  enough 
more  of  the  volumetric  acid  to  surely  dissolve  all  the  alkaloids,  avoiding  excess 
of  acid,  and  filter  through  a  filter  as  small  as  possible,  washing  with  the  least 
quantity  of  hot  water  and  a  few  drops  of  acid  from  the  burette,  until  a  drop  or 
two  of  the  washings  cease  to  react  for  quinine  when  tested  with  a  drop  of  May- 
er's solution.  To  the  filtrate  add  of  decinormal  solution  of  soda  as  many  c.c.  as 
have  been  added  of  the  acid  beyond  the  point  of  just  perceptible  acidity,  bring- 
ing back  the  reaction  to  this  point. 

2 Then  (c.c.  of  decinormal  acid  —c.c.  of  alkali)  X  0.03  [0.0324  to  0.0294]= 
nearly  the  quantity  of  total  cinchona  alkaloids  present,  in  grams.  But  observe 
that  if  the  alkaloids  have  been  precipitated  with  soda,  incomplete  washing  may 
have  left  behind  sufficient  alkali  to  affect  the  result. 

3 Or  to  make  the  whole  measure  of  c.c.  a  number  equal  to  2.1  X  (c.c.  of 
decinormal  acid — c.c.  of  alkali). 

40r  until  the  liquid  measures,  in  c  c.,  2.7  times  (c.c.  of  decinormal  acid  — 
c.c.  of  alkali). 

6  The  U  S.  Ph.  directs  to  dry  at  60°  C.  (140°  F.)  to  a  constant  weight  as 
effloresced  sulphate  (2H20).  Of  this  weight  11.5  per  cent,  is  added  to  give  the 
quantity  of  crystallized  salt  (7H20). 

6 To  represent  seven  molecules,  or  14.45  per  cent,  crystallization  water. 
See  under  Quinine  ( f). 

7 That  is,  add  0'.0012  of  weight  of  crystals  for  each  c.c.  of  total  filtrate. 
This  correction  presumes  that  the  saturated  solution  (£•  of  the  filtrate)  shall 
carry  in  solution  0.135  per  cent,  of  crystallized  salt  (1  to  740),  and  that  the 
washings  (f  of  the  filtrate)  shall  hold  0.067  per  cent,  of  cryst.  salt,  which  is 


ii6  CINCHONA  ALKALOIDS. 

the  entire  filtered  liquid  (for  solubility  of  the  crystals  at  15°  C ) " 
The  sum  equals  the  quantity  of  quinine  as  crystallized  sulphate 
in  the  mixed  alkaloids  taken.  If  from  20  grams  of  the  bark, 
multiply  by  5  to  convert  to  percentage.  Of  the  crystallized  sul- 
phate (7H3O),  74.31  per  cent,  is  anhydrous  quinine. 

Separation  of  Quinine  (I.  A,  3)  from  other  cinchona  alka- 
loids by  ether. — The  ether  solubilities  of  the  alkaloids  taken  sepa- 
rately are  for  good  ether  very  nearly  as  follows,  at  15°  C. :  quinine 
in  25  parts  of  the  ether,  quinidine  in  30  parts,  cinchonidine  in 
188  parts,  and  cinchonine  in  371  parts  of  ether.  The  amorphous 
alkaloids  of  cinchona  have  in  general  a  very  considerable  solu- 
bility in  ether.  Quinidine  occurs  in  so  small  quantities  that  its 
solubility  is  not  regarded.  But  the  different  factors  of  solubility 
above  stated  are  not  available  for  separation,  because,  as  every 
analyst  experiences,  they  do  not  hold  true  in  mixtures  of  the 
alkaloids.  Thus  in  a  mixture  of  quinine  and  cinchonidine,  qui- 
nine is  less  soluble  and  cinchonidine  is  more  soluble  in  ether  than 
when  these  alkaloids  are  taken  separately.1  Nevertheless,  sepa- 
ration by  ether  has  been  in  use  by  quinologists  more  than  any 
other  separation.  An  analyst  of  bark  learns  by  the  manufac- 
turer's results  so  to  adjust  the  application  of  the  ether  that,  for 
example,  about  as  much  of  quinine  will  remain  undissolved  as 
there  is  of  cinchonidine  in  solution.  The  use  of  ether  in  testing 
quinine  for  presence  of  cinchonine  is  credited  to  LiEBiG2  in  the 
test  which  bears  his  name.  For  use  of  ether  in  the  assay  of  the 
mixed  alkaloids  for  quinine,  or  for  ether-soluble  alkaloids,  the 
author  prefers  the  very  practical  directions  of  Dr.  SQUIBB,  who 
prefaces  the  following  instructions 3  by  the  statement  that  u  it 

half  saturation.  The  degree  of  partial  saturation  of  the  washings  (if  held  at 
15°  C.)  is  subject  to  the  rate  of  application  of  the  wash-water  and  its  retention 
in  the  filter.  Six  experiments  of  the  author  with  Mr.  Thum  (1878:  Proc.  Am. 
Pharm.,  26,  834)  gave  a  mean  result  equivalent  to  0.00095  of  crystallized  sul- 
phate for  each  c.c.  of  filtrate  (stated  as  0.00085  of  effloresced  sulphate  for  each 
c.c.)  The  exact  average  figures  as  0.00081  of  effloresced  salt  for  each  c.c.  J. 
MUTER  (1880:  Analyst,  5,  224)  adds  0.000817  of  crystallized  sulphate  for  each 
c.c.  of  total  filtrate,  a  filtrate  which  is  about  80  per  cent,  saturated  solution  and 
20  per  cent,  washings.  Further  evidence  on  the  rate  of  this  correction  is  desira- 
ble. The  0.12  per  cent,  correction  may  be  too  large.  It  is  stated  by  CARLES 
(1872)  that  the  solubility  of  the  quinine  sulphate  is  diminished  by  presence  of 
ammonium  sulphate ;  by  SCHLICKITM  (1885)  that  it  is  greatly  diminished  by  pre- 
sence of  sodium  sulphate.  But  these  facts  seem  to  afford  no  aid  in  separation  of 
clean  sulphate  of  quinine  for  weight,  unless  by  a  resort  to  washing  with  saturated 
solution  of  quinine  sulphate  and  a  correction  proportional  to  the  drying-loss. 

Experimental  results  are  given  by  PAUL,  1877.  KOPPESCHAAR  (1885: 
Ztits.  anal.  Chem.,  24,  362)  infers  that  quinine  and  cinchonidine  unite  in  a 
compound  which  is  readily  soluble  in  ether. 

2  A  note  on  the  history  of  the  test  is  given  under  Quinine,  g. 

'1882:  Ephemeris,  i,  111. 


SEPARATION  OF  QUININE.  117 

seems  only  practicable,  in  a  general  way,  to  reach  near  approxi- 
mations by  some  method  which  is  simple  and  easy  of  applica- 
tion "  : 

"  Into  the  Hask  containing  the  total  alkaloids  [from  5  grams 
bark,  or  10  grams  if  poor  in  alkaloids],  after  these  have  been 
weighed,  put  first  5  grams  of  glass  which  has  been  ground  up  in 
a  mortar  to  a  mixture  of  coarse  and  fine  powder,  and  then  5  c.c. 
of  stronger  ether  (sp.  gr.  not  above  0.725  at  15°  C.)  Cork  the 
flask  and  shake  it  vigorously  until  by  means  of  the  glass  all  the 
alkaloids  have  been  detached  from  the  flask  and  ground  up  in 
the  presence  of  the  ether  into  fine  particles.  In  this  way  the 
definite  quantity  of  ether,  which  is  large  enough  to  dissolve 
all  the  quinine  that  could  possibly  be  present,  becomes  entirely 
saturated  with  alkaloids  in  the  proportion  of  their  solubility,  and 
the  solution  will  necessarily  embrace  all  the  soluble  ones  as  the 
quinine. — Next  mark  two  test-tubes  at  the  capacity  of  10  c.c. 
each,  and  place  a  funnel  and  a  filter  of  7  centimeters  (2.8  inches) 
diameter  over  one  of  them.  Wet  the  filter  well  with  ether,  and 
then  pour  on  to  it  the  mixture  of  alkaloids,  ether,  and  glass  from 
the  flask.  Rinse  the  flask  out  two  or  three  times  on  to  the  filter 
with  fresli  ether,  and  then  wash  the  filter,  and  percolate  the  glass, 
with  fresh  ether,  applied  drop  by  drop  from  a  pipette,  until  the 
liquid  in  the  test-tube  reaches  the  10  c.c.  mark.  Then  change 
the  funnel  to  the  other  test-tube,  and  continue  the  washing  and 
percolation  with  ether  until  the  mark  on  the  second  test-tube  is 
reached  by  the  filtrate.  Pour  the  contents  of  the  two  test-tubes 
into  two  small  tared  capsules,  evaporate  to  a  constant  weight,  and 
weigh  them.  The  first  capsule  will  contain  what  may  be  called 
the  ether-soluble  alkaloids.  Subtract  from  the  weight  of  these 
the  weight  of  the  residue  in  the  second  capsule,  and  the  re- 
mainder will  be  the  approximate  weight  of  the  quinine  extracted 
from  the  5  grams  of  bark."  These  weights  multiplied  by  20  will 
give  the  percentage  of  ether-soluble  alkaloids  and  of  quinine." — It 
is  here  understood  that  the  terms  "  ether-soluble  alkaloids  "  and 
"  quinine  "  have  a  conventional  meaning.  And  the  conclusion  is 
adopted  that  the  quinine  is  all  or  nearly  all  obtained  in  the  first 
10  c.c.  of  filtrate,  while  of  the  less  soluble  alkaloids  nearly  equal 
quantities  are  obtained  in  the  first  and  the  second  10  c.c.  of 
filtrates.  Therefore  the  subtraction  of  the  weight  of  the  second 
residue  from  the  weight  of  the  first  will  give  an  approxima- 
tion to  the  weight  of  the  quinine. 

Separation  of  Quinine  (I.  A,  4)  from  other  cinchona  alka- 
loids by  solution  in  excess  of  ammonia,  after  crystallization  of 
the  sulphate.  An  adaptation  of  Kernels  volumetric  method. 


ii8  CINCHONA  ALKALOIDS. 

More  fully  studied  for  Cinclionidine  than  for  quinidine  or  cin- 
chonine.1  Application  to  a  Precipitate  or  Residue  of  Qui- 
nine with  S7nall  proportions  of  Cinchonidine  (I.  B,  2). — The 
precipitate  or  residue  is  dried  finally  on  the  water-bath  to  a 
constant  weight,  and  a  weighed  quantity,  from  3  to  5  grams,  of 
the  dried  alkaloids  is  taken.  The  alkaloids  are  treated  with 
warm  dilute  sulphuric  acid  added  with  a  little  hot  water  to  make 
the  reaction  just  distinctly  acidulous  to  litmus-paper,  and  retain 
this  reaction  after  the  alkaloids  have  been  thoroughly  saturated, 
when  the  mixture  is  exactly  neutralized  by  adding  dilute  am- 
monia-water, and  made  up  at  temperature  near  100°  C.  to  a  number 
of  c.c.  equal  to  14.5  times  the  number  of  grams  of  dried  alkaloid 
taken.  The  container  is  now  placed  in  a  bucket  of  water  at 
about  15°  C.,  along  with  a  bottle  of  Standard  Quinine  Sulphate 
Solution  (see  Index)  and  a  bottle  of  ammonia- water  of  sp.  gr. 
0.920,  and  the  same  temperature  maintained  for  an  hour  or 
more,  and  adjusted  at  15°  C.  near  the  close  of  this  time.  The 
two  alkaloidal  solutions  are  now  filtered  through  dry  filters,  and 
the  filtrates  received  in  portions  of  10  c.c.  each,  in  test-tubes 
— the  standard  quinine  filtrates  on  one  side,  and  the  filtrates  from 
the  alkaloids  to  be  estimated  on  the  other  side.  The  filtrates  are 
titrated,  in  repeated  trials,  by  adding  ammonia  from  a  burette 
(registering  -fa  c.c.),  until,  on  gently  inclining  or  rotating  the  test- 
tube  while  it  is  closed  by  the  finger,  the  precipitate  at  first 
formed  is  just  redissolved. — Should  the  first  10  c.c.  of  filtrate 
under  estimation  require  more  than  about  4.8  c.c.  of  the  ammonia 
(0.920),  after  deducting  the  c.c.  taken  for  10  c.c.  of  the  standard 
quinine,  then  a  10  c.c.  filtrate  under  estimation  should  be  diluted, 
by  addition  of  the  standard  quinine  filtrate,  to  2,  3,  or  4  times  the 
10  c.c.  volume  (20,  30,  or  40  c.c.),  and  portions  of  10  c.c.  of  this  di- 
luted filtrate  tested.  The  results  of  these  tests,  after  deducting  the 
average  c.c.  of  ammonia  for  10  c.c.  of  standard  quinine  iiltrate, 
are  multiplied  by  2,  3,  or  4,  to  give  the  proper  quantity  of  am- 
monia for  10  c.c,  of  the  filtrate  under  estimation. — Taking  now 
the  mean  of  the  several  titrations  for  10  c.c.  filtrate  under  esti- 
mation, after  deducting  the  mean  of  titrations  of  standard  qui- 
nine filtrate,  each  0.32  c.c.  =  0.1  per  cent,  cinchonidlne  in  the 
mixed  alkaloids  estimated. 

SEPARATION  OF  CINCHONIDINE  (II.  A,  1)  from  other  cinchona 
alkaloids  in  general,  after  removal  of  quinine,  ~by  precipitation 

1  KEENER,  1862.     Improved  in  1880:  Zeitsch.  anal.  Chem.,  20    ,/ifl;  Archiv 
d.  Phar.,  [3],  16, 186-285;  17,  488-454;  Jour.  Chem.  Soc.,  40,  63 
in  this  work,  under  Quinine,  g,  "Kerner's  Test." 


SEPARATION  OF  CINCHONIDINE.  119 

with  normal  tartrate. — The  quinine  may  be  removed  (1)  by 
crystallization  as  a  sulphate  (p.  114),  or  (2)  by  solution  in  ether 
(p.  116).  For  the  purpose  of  an  estimation,  a  deduction  of  the 
quantity  of  quinine  from  the  quantity  of  both  quinine  and  cin- 
chonidine  is  quite  sufficient.  To  this  end  the  following  direc- 
tions of  MUTER,  1  here  slightly  varied,  serve  well : 

The  quinine  is  separated  and  estimated  as  crystalline  sulphate 
(p.  114),  A  weighed  portion  of  the  mixed  cinchona  alkaloids  is 
dissolved  with  hydrochloric  acid  enough  to  make  the  solution 
only  slightly  acid2  to  test-paper,  and  as  concentrated  as  compa- 
tible with  solution  at  38°  C.  (or  100°  F.) 3  The  solution  is  made 
exactly  neutral  by  adding  sodium  hydrate  dilute  solution,  an  ex- 
cess of  the  precipitant,  a  saturated  solution  of  tartrate  of  potas- 
sium and  sodium  (Kochelle  salt)  is  added,  and  the  mixture  kept  at 
15°  C.  (59°  F.)  for  an  hour,  stirring  frequently  with  a  glass  rod. 
The  precipitate  is  collected  on  a  pair  of  filters  as  small  as  practicable 
and  previously  (dried  and)  counterbalanced  with  each  other,  and  is 
washed  with,  say,  100  c.c.  of  water  at  15°  C.,  the  filtrate  and  wash- 
ings being  received  in  a  graduated  measure.  The  precipitate  is 
dried  at  104°  C.  (or  at  220°  F.)  and  weighed,  using  the  outer 
filter  as  a  tare.  For  each  c.c.  of  the  total  filtrate  0.00083  is 
added  (MUTEK)  to  the  weight  of  the  precipitate.  The  weight  of 
anhydrous  quinine  sulphate  is  multiplied  by  0.9151,  or  the 
weight  of  anhydrous  quinine  is  multiplied  by  1.231,  to  obtain 
the  weight  of  anhydrous  quinine  tartrate,  which  is  deducted 
from  the  weight  of  the  precipitate.  The  remainder  is  the  weight 
of  anhydrous  cinchonidine  tartrate  (Ci9H22N2O)2C4H6p6 ,  which, 
multiplied  by  0.796T,  gives  the  weight  of  cinchonidine.  (For 
following  separation  of  remaining  alkaloids  see  p.  120). 

/Separation  of  Cinchonidine  (II.  A,  2)  ~by  precipitation  as 
tartrate,  followed  by  removal  from  Quinine.  This  plan  differs 
from  the  preceding  only  in  the  order  of  the  successive  steps. — 
In  precipitating  first  as  tartrate,  in  case  of  Commercial  Quinine 
Sulphate,  DE  YKIJ  (1884)  directs  to  take  5  grams  of  the  salt,  in 
200  c.c.  boiling  water,  and  add  5  grams  of  Kochelle  salt  previously 
dissolved  in  very  little  boiling  water.  After  24  hours  collect  on 
a  filter,  wash  with  the  smallest  quantity  of  water,  and  dry  in  the 

'ISSO:  Analyst,  5,  224. 

2  Muter  dissolves  the  mixed  alkaloids  in  absolute  alcohol,  divides  in  two 
equal  portions,  taking  one  portion  for  quinine  as  a  sulphate.     The  portion  for 
cinchonidine  is  made  just  acid  with  hydrochloric  acid,  the  alcohol  evaporated 
off,  and  t  he  residue  dissolved  in  least  quantity  of  water  at  100°  F. 

3  If  the  total  alkaloids  contain  resins,  kinic  acid,  etc  ,  filter  through  a 
small  filter,  wash  with  as  little  dilution  as  possible,  and  if  necessary  concen- 
trate. 


120  CINCHONA  ALKALOIDS. 

air. — KOPP  states  that  a  double  normal  tartrate  of  quinine  and 
cinclionidine  crystallizes  with  1  molecule  of  water. — HEILBIG 
(1880),  following  De  Vrij,  separates  cinchona  alkaloids  in  gene- 
ral, by  initial  precipitation  of  tart  rates,  as  follows :  2  grams  of 
the  mixed  alkaloids  are  dissolved  as  acetates  in  30  c.c.  of  water, 
and  the  solution  mixed  with  1  gram  Rochelle  salt  and  well 
stirred.  The  precipitate  is  washed  with  care  to  avoid  its  solution, 
and  dissolved  in  90  per  cent,  alcohol  acidulated  with  1.6  per  cent, 
of  sulphuric  acid,  and  herapathite  is  formed  (as  directed  under 
Quinine,  /'). — The  filtrate  is  treated  with  potassium  iodide  for 
precipitation  of  quinidine.  The  filtrate  from  the  latter  is  treated 
with  soda,  and  the  resulting  precipitate,  dried,  is  exhausted  by 
absolute  ether  for  removal  of  amorphous  alkaloids,  the  remainder 
being  cinchonine. 

.for  separation  of  Cinchonidine,  Quinidine,  Cinchonine, 
and  Amorphous  Alkaloids  from  each  other,  after  the  estima- 
tion of  Quinine,  the  directions  of  DE  VRIJ  are  as  follows :  "  Two 
grams  of  the  pulverized  mixed  alkaloids  are  dissolved  in  weak 
Hydrochloric  acid  to  obtain  a  slightly  alkaline  solution  measur- 
ing 70  c.c.  By  adding  1  gram  of  Rochelle  salt  to  this  solution," 
heating,  cooling,  stirring,  and  setting  aside,  as  above  indicated, 
"  the  tartrates  of  quinine  and  cinclionidine  are  separated ;  these 
are  collected  on  a  filter,  washed  with  a  little  water,  and  dried  on 
a  water-bath.  One  part  of  these  tartrates  represents  0.80844  of 
quinine  and  cinchonidine :  from  the  amount  of  these  alkaloids 
thus  found  the  amount  of  quinine  already  ascertained  is  sub- 
tracted, the  remainder  representing  the  cinchonidine  present." — 
"  In  the  filtrates  from  the  tartrates,  quinidine,  if  present,  is  pre- 
cipitated by  a  concentrated  solution  of  potassium  iodide  [compare 
under  Quinidine,  d  and  f~\  ;  one  part  of  the  dried  hydriodide  re- 
presents 0.86504  part  of  crystallized  quinidine  [0.7175  part  of 
anhydrous  quinidine]." — "  The  remaining  solution  is  treated  with 
caustic  soda,  and  the  precipitate  (if  any)  washed  with  ether.  The 
residue  represents  the  amount  of  cinchonine  (compare  under  Cin- 
chonine, /*)." — "  Finally,  by  distilling  the  ether  from  the  wash- 
ings can  be  ascertained  the  amount  of  amorphous  alkaloid, 
which  often,  in  the  case  of  analysis  of  Indian  barks,  contains 
traces  of  quinamine" 

The  directions  of  J.  MUTER,'  for  separation  of  Quinidine, 
Cinchonine,  and  Amorphous  Alkaloid,  taking  the  filtrate  from 
Cinchonidine  and  Quinine  tartrates  (see  p.  119),  are  as  follows : 
"The  filtrate  from  the  tartrate  is  concentrated  to  its  original 

1 1880  :  Analyst,  5,  224. 


ROTATORY  POWER.  121 

volume  [that  before  the  washing  of  the  precipitate  is  probably 
intended],  cooled,  rendered  just  faintly  acid  by  a  drop  of  dilute 
acetic  acid,  and  excess  of  saturated  solution  of  potassium  iodide 
is  added  with  constant  stirring.  After  an  hour  or  so  at  15°  C. 
[compare  under  Quinidine,  f\  it  is  collected  like  the  cinchoni- 
dine,  and  treated  in  every  respect  the  same,  and  weighed,  and 
the  weight,  having  had  0.00077  added  for  each  c  c.  of  filtrate 
and  washings,  is  multiplied  by  [0.7175],  and  result  is  quinidine" 
— "  The  filtrate  from  the  quinidine  is  made  distinctly  alkaline  by 
sodium  hydrate,  and  the  precipitated  cinchonine  and  amorphous 
alkaloid  are  filtered  out  in  a  similar  manner,  washed,  dried,  and 
weighed.  The  precipitate  is  then  treated  with  alcohol  of  40  per 
cent,  to  dissolve  out  the  amorphous  alkaloid,  and  again  dried  and 
weighed,  and  the  difference  is  amorphous  alkaloid,  while  the 
last  weighing  is  cinchonine."  But  "  the  weight  of  the  cincho- 
nine and  amorphous  alkaloid  together  must  have  deducted  from 
it  0.00052  for  each  c.c.  of  the  filtrate  from  the  quinidine  hydrio- 
dide,  and  0.00066  for  each  c.c.  of  the  filtrate  from  the  cinchoni- 
dine  tartrate,  and  the  balance  is  then  the  true  weight,  which, 
minus  the  amorphous  alkaloid,  gives  the  cinchonine" 

KOTATOKY    POWEK,    OF   CINCHONA    ALKALOIDS. 

The  plane  of  polarized  light  is  deviated  to  the  left  by  quinine 
and  cinchonidine,  to  the  right  by  quinidine  and  cinchonine. 
Further,  the  dextrorotatory  alkaloids  include  diquinicine,  quiiii- 
cine,  cinchonicine,  concusconine,  conchairamine,  chairamidiney 
and  cinchotine  ;  the  levorotatory  alkaloids  include  hydroquinine, 
hydroquinidine,  hydrocinchonidine,  homoquinine,  cusconine,  con- 
chairamidine,  paytine,  aricine,  and  cinchamidine. — The  degree  of 
deviation,  or  specific  rotatory  power,  varies  between  the  free 
alkaloid  and  its  salts,1  and  varies  with  different  solvents,  concen- 
trations, and  temperatures. 
Quinine  hydrate,  in  alcohol  97$  vol.,  at  15°  C., 

[a]  D=-(145.2°-0.657c 2) HESSE,   1875. 

Quinine  hydrate  in  ether    (0.7296),  at  15°  C., 

[a]  D— — (158.7°— 1.911c) "  " 

Quinine,  anhyd.,  5$  sol   in  chloroform,  15°  C., 

[a]  D=-106.6° "  " 

Between  15°  C.  and  25°  C.,  when  c=3,  ab- 
solute rotatory  power  falls  1.56° "  " 

*  Further  as  to  the  influence  of  the  acids,  OUDEMANS,  1883;  as  to  influence 
of  solvents,  the  same  author,  1873. 

2c  =  concentration,  or  grams  in  100  c.c.  of  solution. 


122  CINCHONA   ALKALOIDS. 

Quinine  sulphate,  cryst.,  in  alcohol  80$  vol., 

(c=2),  15°  C.,  [a]  D=  -162.95° HESSE,  1875. 

Quinine  sulphate,  cryst.,  in  alcohol  60$  vol., 

(c=2),  15°  C.,  [a]  D=  -166.36° .' 

Quinine  bisulphate,  cryst.,  in  water,  (c=l  to  6), 

15°  C.,  \a\  D=-(164.85°-0.31c) "  " 

Quinine  sulphate,  anhyd.,  in  water,  (c— 4),  15°  C., 

[a]  D=:-229.03° "         1880. 

Quinine  sulphate,  anhyd.,  in  water,  (c=l),  15°  C., 

[a]  T>=— 232.7° DAVIES,  1885. 

Quinine  sulphate,  anhyd.,  in  water,  (c=4).  15°  C., 

[a]  D=  —233.75° '. HESSE,   1886. 

Quinine  sulphate,  anhyd.,  in  water,  17°  C.,  [a\  D 

=—242  17° OUDEMANS. 

Quinine  hydrochloride,  in  water,  (c=l  to  3), 

15°  C.\  [a]  D=— (165.5°  — 2  425c) HESSE. 

Cinchonidine,  in  alcohol  of  97$  vol.,  (c=l  to  5), 

15°  C.,  [a]  D=-(107.48°-0.297c), " 

Cinchonidine  sulphate,  6  aq.,  in  water,  (c=1.06), 

15°  0.,  [a]  D=-106.77° " 

Cinchonidine  sulphate,  anhyd.,  in  2.156$  sol.  in 

alcohol,  [a]  D==:-153.950 " 

"With  0.40  gram  of  the  salt,  with  3  c.c.  normal  solution  hy- 
drochloric acid,  and  water  to  make  a  volume  of  20  c.c  ("  Con- 
centration A  "  of  Oudemans)  : 

Quinine  tartrate,  cryst.,  [a]  D=— 215.8° OUDEMANS. 

Anhyd.=— 220. 07° KOPPESCHAAK. 

Cinchonidine  tart.,  cryst.,  [a]  D=— 131.3°. .  . .  OUDEMANS. 

Anhyd. =—137.67° KOPPESCHAAK. 

Take  0.40  of  mixed  tartrates  of  quinine  and  cinchonidine 
(see  under  Separation  of  Cinchona  Alkaloids  by  Tartrate,  p.  119), 
dry  at  125°  to  130°  C.,  dissolve  as  stated  above  for  "  Concentra- 
tion A,"  observe  rotatory  power  (a),  then,  to  find  x  =  per  cent, 
of  quinine  tartrate  in  the  mixed  tartrates : 

220. 07 a? +  137.67  (100-»)  =  100a. 

_  100(0-137.67)  t 
~220.07-137.67* 
For  the  estimation  of  cinchonidine  in  commercial  quinine 

1  KOPPESCHAAR,  1885:  Zeitsr.h.  anal.  Chem.,  24,  362;  Jour.  Chem.  Soc., 
49,  182.  OUDEMANS,  1875:  Arch,  neerland.  des  Sci.,  10,  193;  Jahr.  Chem., 
1875,  140.  Further,  1877  and  1884. 


RO  TA  TOR  Y  PO  WER.  123 

sulphate  HESSE  J  directs  as  follows  :  2  grams  of  anhydrous  com- 
mercial quinine  sulphate,  or  an  equivalent  quantity  of  crystallized 
salts,  are  weighed  in  a  flask  of  25  c.c.  capacity,  mixed  with  10  c.c. 
of  normal  solution  of  hydrochloric  acid,  the  flask  fllled  up  to  the 
graduation-mark  with  water,  and,  after  the  contents  are  thoroughly 
mixed  by  shaking,  the  solution  is  poured  through  a  filter  into  the 
observation  tube,  which  is  220  millimeters  long  and  is  provided 
with  a  water-jacket  for  maintaining  a  constant  temperature.  From 
12  to  20  observations  are  made  with  this  solution,  at  15°  C.,  and 
the  mean  of  the  different  readings  is  taken.  Let  c  =  the  observed 
deviation  at  the  D  line,  and  y  =  the  cinchonidine  sulphate.8  Then, 
if  the  observation- tube  be  220  m.m.,  y=  (40.309—  c)  X  8.25. 
For  other  lengths  of  the  observation-tube  let  C  =  the  observed 
rotatory  power,  when  y  =  (229.03  —  C)  X  1.452. 
Quinidine,  deviation  diminishes  with  elevation  of 

temperature. 
Quinidine  hydrate,  in  alcohol  of  97$  vol.,  at  15°  C., 

[a]  D=r+(236.T7°— 3.01c) HESSE. 

Quinidine  anhyd.,  in  alcohol  of  97$  vol.,  at  15°  C., 

[«]  D=+(269.57°-3.428c) " 

Quinidine  hydrochloride,  in  alcohol  of  97$,  at  15°  C., 

[a]  D=H-(212°-2.562c) " 

Cinchonine,  in  alcohol,  c=0.455,  [a]  D=-f-214.8° 
c=0.535,          =     213.3° 

ci=0.560,         =     209.6° OUDEMANS. 

Cinchonine   sulphate,   in    water,  c  =  0.855,  [a]  D= 

+170° HESSE. 

Cinchonine  sulphate,  in  97$  alcohol,  c  =  0.374,  [a]  D 

=+193.29° " 

Cinchonine  hydrochloride,  [a]  D=+(165°— 2.425c).. 
Quinicine,  in  97$  alcohol  with  chloroform,  [a]  D:= 

-f(10.68°-1.14c). 
Cinchonicine,  in  chloroform,  at  15°  C.,  [a]  o=-[-46.50. 

1 1880:  Liebig's  Annalen,  205,  217;  Jour.  Chem.  Soc.,  40,  315.  Also,  1885: 
Phar.  .four.  Trans.,  [3],  15,  869. 

2  If  a  be  the  angle  of  rotation  of  dry  quinine  sulphate,  b  th*  angle  of  anhy- 
drous cinchonidine  sulphate,  and  c  the  "angle  of  the  mixture,  then  if  x  be  the 
quantity  of  quinine  sulphate,  and  y  the  quantity  of  cinchonidine  sulphate,  the 

relative  percentage  of  the  last-named  salt  is  expressed  by  the  formula  y  =  — — ^. 
For  a  and  b  Hesse  has  found  the  numbers  —40.309°  and  —26.598°;  there- 
fore y  =  40;f°f~C ,  or,  taking  y  as  percentage,  y  =  (40. 309 -c)  7.293.  On  ac- 

lo.711 

count  of  the  common  efflorescence  of  cinchonidine  sulphate,  Hesse  modifies  the 
formula  to  y  =  (40. 309 -c)  8.25. 


124  CINCHONA   ALKALOIDS. 

A  single  determination  in  a  given  solvent  obviously  cannot  be 
used  for  estimation  when  more  than  two  alkaloids  of  cinchona 
are  present.  But  by  use  of  different  solvents,  or  different  tem- 
peratures and  concentrations,  it  has  been  proposed  to  undertake 
estimation  in  mixtures  of  three  alkaloids.  OUDEMANS  has  stated 
that  optical  estimation  is  practicable  in  the  following-named  mix- 
tures :  quinine  and  cinchonidine  ;  quinine  and  quinidine  ;  quini- 
dine  and  cinchonidine ;  quinine  and  cinchonine ;  cinchonidine 
arid  cinchonine ;  quinine,  quinidine,  and  cinchonidine ;  quinine, 
quinidine,  and  cinchonine ;  'quinidine,  cinchonidine,  and  cincho- 
nine ;  quinine,  cinchonidine,  and  cinchonine ;  and  tartrate  of 
quinine,  and  cinchonidine.  KOPPESCHAAR  '  has  advocated  the  su- 
perior efficiency  of  the  optical  way  of  estimating  cinchona  alka- 
loids, and  DAviEs,2  in  report  of  the  extended  research  already 
cited,  expresses  confidence  in  the  optical  estimation  of  cinchoni- 
dine in  commercial  quinine  sulphate.  HESSE,  who  engaged  ex- 
tensively in  optical  researches  upon  the  cinchona  alkaloids  in 
1875,3  and  published  an  optical  method  of  valuation  of  quinine 
sulphate  in  1880,4  in  1886 5  admits  a  diminished  confidence  in  the 
optical  method  for  exact  estimations,  and  says  that  "  up  to  the 
present  moment  we  are  not  in  possession  of  any  optical  test  by 
which  we  would  be  able  to  determine  the  amount  of  cinchoni- 
dine in  commercial  quinine  sulphate  and  other  quinine  salts  with 
any  satisfactory  degree  of  accuracy."  And  u  while  constant  rota- 
tory power  in  two  successive  recrystallizations  of  the  same  mate- 
rial [quinine  sulphate]  is  satisfactory  evidence  of  absence  of  cin- 
chonidine in  that  particular  material,  it  is  not  by  any  means  the 
case  that  the  rotatory  power  of  similar  materials  of  different  ori- 
gin is  always  the  same."  PAUL"  has  stated  "that  the  results  by 
the  polariscope  are  much  less  trustworthy  than  those  by  other 
methods."  KEENER7  holds  it  to  be  manifestly  impracticable  to 
determine  proportions  of  1  and  \\  per  cent,  of  cinchonidine  sul- 
phate, in  mixtures  of  quinine  sulphate,  with  even  minute  propor- 
tions of  cinchonine  and  quinidine  sulphates. 

The  influence  of  hydroquinine  salt,  in  the  optical  valuation  of 
quinine  sulphate,  is  emphasized  by  HESSE  in  the  communication 

'1885:  Phar.  Jour.  Trans.,  [3],  15,  809. 
*1885:  Phar.  Jour.  Trans.,  [3],  16,  358. 
'Liebig'8  Annalen,  176,  203-283. 
*Liebig's  Annalen,  205,  217-222 

6 Phar.  Jour.  Trans.,  [3],  16,  818,  March  27,  1886.  Further,  same  journal, 
June  5,  1886. 

•1885:  Phar.  Jour.  Trans.,  [3],  16,  361. 
'1880:  Archiv  d.  Phar.,  [3],  16,  449. 


QUININE.  12$ 

last  above  cited  from  this  author.1  He  places  the  rotatory  power 
of  the  three  alkaloids  chiefly  concerned  in  the  estimation  of  com- 
mercial quinine  sulphate  as  follows.  The  conditions  of  OUDE- 
MANS  (p.  122)  are  adopted : 

For  concentration  A :  Quinine  tartrate  (a)  D  =  216.6° 
Cinchonidine  tartrate  134.6° 

For  concentration  B  :  Quinine  tartrate  212.5° 

Hydroquinine  tartrate  176.9° 

Cinchonidine  tartrate  132.0° 

Oudemans's  own  results  were  (see  p.  122) : 

For  concentration  A :  Quinine  tartrate          (a)  D  =  215.8° 

Cinchonidine  tartrate  131.3° 

For  concentration  B  :  Quinine  tartrate  211.5° 

Cinchonidine  tartrate  129.6° 

QUININE. — Chinin.  C20H241^2O2— 324.  Crystals  of  full  hy- 
dration,  C20H24N2O2.3H2O==378.  Eational  Formula,  p.  98. 
Proportion*  in  Cinchona  Barks,  p.  96.  Accompanying  Natural 
Alkaloids,  p.  90.  Methods  of  quantitative  separation  from  Cin- 
chona Bark,  p.  102 ;  from  other  Cinchona  Alkaloids,  p.  113. 
Means  of  Distinction  from  other  Cinchona  Alkaloids,  schedule, 
p.  100.  Microscopic  identilication,  p.  101.  Optical  Rotation, 
p.  121.  Crystallization  and  Heat-Reactions  of  the  free  alkaloid 
and  its  salts,  p.  126.  Solubilities  of  the  alkaloid  and  of  its  salts, 
p.  128.  Physiological  effects,  p.  127. 

Quinine  is  recognized  by  the  fluorescence  of  its  sulphate  solu- 
tion (d\  its  bitterness  (5),  and  the  sparing  solubility  of  its  sul- 
phate in  water  (c).  It  is  identified,  further,  by  the  thalleioquin 
test,  the  agreement  of  various  reactions,  and  the  formation  of 
herapathite  (d).  The  separation  of  quinine  from  other  cinchona 
alkaloids  is  indexed  at  p.  Ill ;  from  the  bark,  given  on  pp.  102 
to  111 ;  from  impurities  of  its  commercial  salts,  and  from 
various  common  alkaloids,  also  from  Citrate  of  Iron,  and  from 
Coated  Pills,  page  134.  Means  of  separation  are  noted  under  e. 
Quinine  is  estimated,  as  stated  under  g,  by  weight  of  the  free 
alkaloid,  by  weight  of  the  sulphate,  by  weight  of  the  iodomer- 
curate,  by  titration  with  Mayer's  solution,  and  by  weight  of  crys- 
tallized herapathite.  The  impurities  and  deficiencies  of  quinine 

1  For  a  brief  summary  of  the  claims  of  De  Vrij  and  Hesse  see  Am.  Jour. 
Phar.,  1886,  Aug.,  58,  389,  editorial.  Respecting  optical  estimations  of  qui- 
nine, treating  the  tartrates  of  the  alkaloids,  a  paper  is  presented  by  D.  HOOPER, 
Ootacamund,  India,  1886:  Phar.  Jour.  Trans.,  [3],  17,  61. 


126  CINCHONA   ALKALOIDS. 

salts  (under  g)  are  chiefly  the  other  cinchona  alkaloids,  and 
varied  quantities  of  water.  The  other  cinchona  alkaloids  are 
subject  to  test  by  Kerner's  method,  qualitative  or  quantitative, 
and  given  for  salts  other  than  sulphate,  the  free  alkaloid,  the 
bisulphate,  and  for  effloresced  salts.  Tests  are  given  by  Hesse's 
method,  and  by  the  directions  of  the  pharmacopoeias  of  the  dif- 
ferent nations.  Concerning  Liebig's  test,  and  standards  of  water 
of  crystallization,  a  full  discussion  is  included  under  g. 

a. — Free  quinine  usually  appears  in  an  amorphous  or  curdy 
or  minutely  crystalline  white  powder,  or  in  crystals  slightly  efflo- 
resced. The  trihydrate  (3H2O)  forms  needles,  sometimes  long 
and  silky.  Crystallizing  under  the  microscope,  four- sided  prisms 
are  obtained.  The  precipitate  by  alkalies  from  aqueous  solution 
of  quinine  salts  is  at  first  amorphous  and  anhydrous,  but  gradu- 
ally assumes  crystallization  as  the  trihydrate.  From  warm,  dilute 
alcoholic  solution  anhydrous  crystals  have  been  obtained  (HESSE, 
1877).  From  ether,  and  most  solvents  other  than  water  and  alco- 
hol, crystals  are  never  obtained.  A  dihydrate  (2H2O)  and  a  crys- 
tallizable  monohydrate  (H2O)  have  been  reported  ;  also  an  amor- 
phous hydrate  with  9H2O.  The  precipitate  by  ammonia,  dried 
in  the  air  at  ordinary  temperature,  and  the  residue  from  solution 
in  ether  dried  in  the  same  way  or  over  sulphuric  acid,  retain  one 
molecule  of  water  (FLETCHER,  1886).  The  trihydrate,  nearly 
permanent  in  the  air,  loses  all  but  about  one  molecule  of  the 
water  slowly  in  the  desiccator,  quickly  on  the  water-bath.  All 
hydrates  lose  water  gradually  in  warm  temperatures,  and  on  the 
water-bath  quickly  lose  all  but  four  or  five  per  cent,  (about  one 
molecule)  of  the  water,  which  is  very  slowly  expelled  (A.  N. 
PALMER,  1876).  At  about  120°  C.  (248°  F.)  a  constant  weight 
of  anhydrous  alkaloid  is  promptly  obtained.  The  trihydrate 
melts  at  57°  C.  (134.6°  F.)  ;  the  anhydrous  alkaloid  melts,  without 
loss,  at  177°  C.  (350.6°  F.)  (HESSE,  1877),  cooling  to  an  opaque, 
crystalline  mass  permanent  in  the  air.  Strongly  heated  above 
the  melting  point,  an  amorphous,  not  crystalline  sublimate  is 
obtained. 

Crystallisation  and  heat- reactions  of  salts  of  quinine.1 — • 
Quinine  sulphate  forms  fragile,  filiform  crystals  on  the  mono- 
clinic  system,  with  7H2O  (KERNER,  1880)  or  8H2O  (HESSE, 
1880).  (See  "  Water  of"  Crystallization,"  etc.,  under  g.)  The 
crystals  are  efflorescent.  The  hydration  is  reduced,  slowly  in 
ordinary  air,  promptly  at  50°  to  60°  C.,  to  2H2O.  The  remain- 
ing water  is  expelled  slowly  at  100°  C.,  or,  by  three  hours'  dry- 

1  For  chemical  formulaB  see  "  Solubilities,"  p.  129. 


QUININE.  127 

ing  in  a  water-oven  (H.  B.  PARSONS,  1884),  more  quickly  at  112° 
to  115°  C.  The  anhydrous  salt  recovers  the  2H2O  by  exposure 
to  the  air.  At  or  above  100°  C.  the  salt  soon  begins  to  suffer 
alteration ;  at  about  160°  C.  it  exhibits  a  greenish  phosphor- 
escence, and  above  this  temperature  it  melts,  with  conversion 
into  quinicine  sulphate,  but  without  loss  of  weight.  The  salt  is 
very  slowly  affected  by  the  light.  On  ignition  it  burns  very 
slowly,  leaving  no  residue  after  complete  combustion. — Quinine 
bisulphate  forms  orthorhombic  four-sided  .  prisms,  or  needles, 
sometimes  nodular  crystals  (7H2O),  efflorescing  in  the  air,  more 
rapidly  in  warm  air,  to  1H2O,  and  becoming  anhydrous  at  100°  C. 
It  melts  in  a  glass  tube  at  80°  C.  (Ph.  Germ.)  When  anhydrous 
it  melts  at  or  below  100°  C.  "At  135°  C.  (275°  F.)  it  is  con- 
verted into  bisulphate  of  quinicine  "  (U.  S.  Ph.),  this  conversion 
beginning  at  the  melting  point,  also  by  exposure  to  sunlight,  and 
being  attended  with  a  yellowish  tinge.  There  is  a  doubly  acid 
salt,  crystallizable,  with  7H2O,  in  prisms. —  Quinine  hydrobro- 
mide  crystallizes  in  lustrous  needles  (H2O),  "  permanent  in  the 
air  but  readily  efflorescing  at  a  gentle  heat"  (U.  S.  Ph.),  and 
becomes  anhydrous  on  the  water-bath. —  Quinine  hydriodide, 
normal,  is  crystallizable  in  light  yellow  needles,  instable,  easily 
altered  to  a  soft,  resinous  mass. — Quinine  nitrate  crystallizes 
with  difficulty  in  very  oblique  prisms  (H2O),  easily  melted  to 
an  oily  mass,  and  becoming  anhydrous  at  100°  C. — Quinine  val- 
erianate  crystallizes  in  pearly,  triclinic  crystals  (H2O),  perma- 
nent in  the  air,  melting  at  about  90°  C.,  becoming  anhydrous 
at  100°  C.,  at  which  temperature  it  also  begins  to  lose  valerianic 
acid. —  Quinine  normal  tartrate,  H2O,  becomes  anhydrous  at 
100°  C. — Quinine  oxalate,  normal,  crystallizes  with  6H2O,  in 
very  fine  needles. 

J. — Quinine  is  odorless,  and  has  a  pure  bitter  taste  of  much 
intensity.  The  persistence  and  intensity  of  the  bitter  taste  of 
quinine  salts  is  in  proportion  to  their  solubility  as  brought  in 
contact  with  the  tongue.  Of  ordinary  forms  administered  the 
tannate  is  the  least  and  the  free  alkaloid  next  least  bitter,  the 
sulphate  being  less  bitter  than  the  bisulphate,  hydrobromide,  or 
hydrochloride. — Quinine  is  poisonous  to  the  lower  forms  of  ani- 
inal  life,  in  this  effect  being  surpassed  among  vegetable  poisons 
only  by  such  as  strychnine  and  morphine  (Bmz).  For  frogs  the 
fatal  dose  is  0.05  to  0.1  gram  (}  to  1|  grain)  internally,  or  about 
0.0025  (|  grain)  subcutaneously.  For  dogs  about  "0.12  gram 
per  kilogram  (-J  grain  per  pound)  of  body-weight  proves  fatal 
(BERNATZIK,  1867).  Infusoria  and  bacteria  are  destroyed  with 


128  CINCHONA   ALKALOIDS. 

somewhat  concentrated  solutions  of  quinine  salts,  quite  variable 
strengths  being  required  for  different  infusoria. — Quinine  is 
antiseptic,  hindering  or  stopping  the  alcoholic,  lactous,  butyrous, 
amygdalous,  and  salicylous  fermentations  (Bmz,  "  Husemann's 
Pflanzenstoffe,"  1884),  not  the  digestive  action  of  pepsin. —  Qui- 
nine is  excreted  in  the  urine  to  the  extent  of  70  to  96  per  cent, 
of  the  amount  taken.  It  appears  in  the  urine  as  early,  fre- 
quently, as  one  hour,  and  usually  disappears  as  soon  as  forty- 
eight  hours,  after  ingestion  (KEENER,  JURGENSEN,  and  FRAU). 
Quinine  is  found  in  the  liver.  In  some  small  part,  also,  it  suf- 
fers conversion  in  the  system  into  amorphous  quinine  [di- 
quinicine?],  and  an  oxidation  product,  Dihydroxyl-quinine 
(C20H24N2O4)  (KERNER),  or,  according  to  SKRAUP,  Chitenine 
(C19H22N2O4).  Kerner  states  that  the  physiological  action  of 
the  oxidized  product  is  much  weaker  than  that  of  quinine.  Chi- 
tenine is  formed  by  action  of  permanganate  on  quinine,  is  insolu- 
ble in  ether,  fluoresces,  and  gives  the  thalleioquin  reaction. 

G. — Solubilities. — Quinine  is  sparingly  soluble  in  water;  quite 
freely  soluble  in  alcohol,  ether,  chloroform,  amyl  alcohol ;  mode- 
rately soluble  in  water  of  ammonia,  benzene,  glycerine  ;  and 
sparingly  soluble  in  petroleum  benzin.  The  alkaloid  trihydrate 
is  soluble  in  1670  parts  water  at  15°  C.  (HESSE),  in  1428  parts 
water  at  20°  C.  (SESTINI,  1867),  in  760  parts  boiling  water  (EEG- 
NAULD,  1875),  in  902  parts  boiling  water  (SESTINI),  in  six  parts 
of  ordinary  alcohol  at  15°  C.,  in  ly^  parts  absolute  alcohol  (REG- 
NATJLD),  in  2  parts  boiling  alcohol  of  90$,  in  "  about  25  parts  of 
ether"  (U.  S.  Ph.),  in  22£  parts  of  ether  at  15°  C.  (REGNAULD), 
in  u  about  5  parts  of  chloroform  "  (U.  S.  Ph.)  The  anhydrous 
alkaloid  is  soluble  in  1960  parts  of  water  at  15°  C.  (HESSE), 
in  about  the  same  proportion  of  ether  required  for  the  hydrate 
(HESSE),  in  (near)  2  parts  chloroform  (PETTENKOFER,  1858),  in 
200  parts  benzene  at  15°  C.  or  30  parts  boiling  benzene  (OuDE- 
MANS,  1874). 

Crystals,  mostly  needle-form,  can  be  obtained  from  nearly  all 
solutions.  From  benzene,  crystals  of  C20H24N2O2-|-C6H6  are 
obtained  (OUDEMANS).  Solubility  in  ether  is  diminished  by  pre- 
sence of  other  cinchona  alkaloids  (PAUL,  1877). 

Quinine  has  a  decided  alkaline  reaction,  promptly  shown  upon 
test-papers  in  the  aqueous  solution.  The  normal  salts  of  the 
stronger  acids  are  neutral  to  litmus,  the  sulphate  of  manufacture 
not -infrequently  alkaline  in  the  least  perceptible  degree. — Quinine 
salts  of  ordinary  acids  are  soluble  or  moderately  soluble  in  water 
and  in  alcohol,  except  the  sulphate,  which  is  only  sparingly  soluble 


QUININE.  129 

in  water.     The  proportion  of  water  required  for  the  free  alkaloid 
at  100°  C.  is  about  that  required  for  the  sulphate  at  15°  C. 

Solubilities  of  quinine  salts.  -  -  Quinine  sulphate, 
(C20H24]^2p2)2H2SO4.7H2O=872,  is  soluble  "  in  740  parts  of 
water  and  in  65  parts  of  alcohol  at  15°  C.  (59°  F.) ;  in  about  30 
parts  of  boiling  water,  in  about  3  parts  of  boiling  alcohol,  in 
small  proportions  of  acidulated  water,  in  40  parts  of  glycerine, 
in  1000  parts  of  chloroform,  and  very  slightly  soluble  in  ether  " 
(IT.  S.  Ph.)  Its  solubility  in  water  is  decreased  by  presence  of  am- 
monium sulphate  (CABLES)  or  sodium  sulphate  (SCHLICKUM,  1885) ; 
in  chloroform  is  increased  by  presence  of  cinchonine  or  quinidine 
-sulphate.  From  acidulous  aqueous  solution  it  is  sparingly  dis- 
•solved  by  amyl  alcohol  (BAKFOED).  In  alcoholic  solution  it  is  pre- 
cipitated by  adding  ether. — Qjuinine  Usulphate,  C20H24N2O2 
H2SO4.7H2O=:548,  is  soluble  "in  about  10  parts  of  water  (with 
vivid  blue  fluorescence)  and  in  32  parts  of  alcohol,  at  15°  C. 
(59°  F.) ;  very  soluble  in  boiling  water  and  in  boiling  alcohol  " 
(U.  S.  Ph.)  It  has  a  strongly  acid  reaction. — The  doubly  acid 
sulphate,  C20H24N2O2(H2SO4)27H2O,  is  freely  soluble  in  water 
and  in  alcohol. — Quinine  hydrobromide,  C00H04N2O2HBr .  H2O 
=422.8,  is  soluble  "  in  about  16  parts  of  water  and  in  3  parts 
of  alcohol,  at  15°  C.  (59°  F.)  ;  in  1  part  of  boiling  water  and  less 
than  1  part  of  boiling  alcohol ;  in  6  parts  of  ether,  in  12  parts  of 
chloroform,  and  moderately  soluble  in  glycerine"  (U.  S.  Ph.) — 
Quinine  hydrochloride  (muriate),  C22H24N2O2HC1.H2O==378.4, 
is  soluble  "in  34  parts  of  water,  and  in  3  parts  of  alcohol,  at 
15°  C.  (59°  F.) ;  in  1  part  of  boiling  water  and  very  soluble  in 
boiling  alcohol ;  when  rendered  anhydrous  it  is  soluble  in  1  part 
of  chloroform  "  (U.  S.  Ph.)  In  9  parts  of  chloroform  (Hager's 
"  Commentar  "  ). — Normal  quinine  hydriodide,  instable,  is  more 
soluble  than  the  sulphate. — Quinine  valerianate,  C20H241S[2O2 
C5H10O2 .  H2O=444,  is  soluble  in  about  100  parts  of  water  and 
in  5  parts  of  alcohol,  at  15°  C.  (59°  F.),  ...  and  slightly  soluble 
in  ether  "  (U.  S,  Ph.) — -Quinine  tannate?  amorphous,  is  but  very 
little  soluble  in  cold  water  (nearly  tasteless),  but  is  soluble  in 
alcohol  and  slightly  soluble  in  ether,  and  by  long  digestion  with 
water  is  converted  into  soluble  quinine  gallate  (LINTNER). — Qui- 
nine tartrate,  normal  (C20H24N2O2)2C4H6O6 .  H2O,  is  soluble  in 
910  parts  of  water  at  10°  C.,  much  more  soluble  in  hot  water 
and  in  alcohol  (HESSE,  1865). — Quinine  oxalate,  (C20H22N2O2)2 

1  JOBST,  1878.  Fluckiger's  "Phar.  Chemie,"425.  Hager's  "  Phar.  Praxis,"  iii. 
291.  Produced  of  very  variable  composition  and  properties.  Ascribed  formula, 
C2oH24N202(Ci4Hio09)3=25  per  cent,  quinine.  Jobst  prepared  it,  31  percent, 
quinine;  and  found  it  in  commerce  from  7  per  cent,  to  22  per  cent,  quinine. 


130  CINCHONA   ALKALOIDS. 

H2C2O4.6H2O,  requires  898  parts  of  water  at  10°  C.  for  solu- 
tion ;  1446  parts  at  18°  C.  (SHIMOYAMA,  1885). 

d. — Fluorescence. — In  general,  quinine  salts  with  inorganic 
acids  containing  oxygen  exhibit  blue  fluorescence  in  their  aqueous 
solutions.  The  hydracids  of  chlorine,  bromine,  etc. ,  the  cyanogen 
hydracids,  and  thiosulphuric  acid,  in  union  with  quinine,  do  not 
give  fluorescence.  By  adding  sulphuric  acid  the  fluorescence  is 
obtained  with  all  the  salts  in  aqueous  solution.  But  the  hydra- 
cids, if  present,  in  proportion  to  their  quantity  diminish  the  reac- 
tion. Alcoholic  solutions  show  little  fluorescence ;  solutions  in 
ether,  chloroform,  etc.,  none  at  all.  The  bisulphate  fluoresces 
much  more  strongly  than  the  normal  sulphate,  in  solutions  of 
equal  strength,  and  the  fluorescence  of  a  neutral  solution  of  the 
sulphate  is  much  intensified  by  acidulating  with  sulphuric  acid. 
— To  obtain  the  full  delicacy  of  the  reaction,  put  the  solution  in 
a  test-tube  or  beaker  of  such  width  that  a  depth  of  at  least  two 
inches  is  obtained.  Place  over  a  black  ground,  in  a  strong  light 
falling  horizontally  from  one  direction,  observing  from  above, 
comparing  with  a  like  column  of  distilled  water,  and,  if  neces- 
sary, shading  the  eye  from  the  direct  light  and  shading  the  liquid 
from  the  lateral  light.  Greater  intensity  is  attained  by  throwing 
the  light  from  a  lens  in  a  pencil  upon  the  liquid.1  So  observed, 
0.00005  gram  quinine,  in  5  c.c.  acidulous  solution,  gives  distinct 
fluorescence,  and  this  (1  in  100000)  is  not  the  limit  of  dilution 
(BARFOED,  1881). — The  fluorescence  of  quinine  is  shared  by  qui- 
nidine,  and  by  diquiniciiie,  hydroquinine,  hydroquinidine ;  not 
by  cinchonidine  nor  by  quinicine. 

Thatteioquin  test. — Treated  in  a  white  porcelain  dish  with 
fresh  chlorine-water  or  bromine-water,  not  in  too  great  excess, 
or  well  diluted,  and  then  with  ammonia  to  just  effect  an  alka- 
line reaction,  a  solution  of  quinine  gives  a  green  precipitate, 
thalleioquin,  dissolving  to  a  green  solution  by  adding  a  further 
excess  of  ammonia.  In  more  dilute  solutions  a  precipitate  is  not 
obtained  at  all,  but  a  green  liquid.  Bromine  gives  with  dilute 
solutions  a  better  result  than  chlorine  (ZELLEK,  1880);  an  exces- 
sive action  of  either  is  to  be  avoided.  According  to  BAKFOED  a 
fine  reaction  is  given  by  0.001  gram  of  quinine,  in  5  c.c.  of  water 
acidulated  with  sulphuric  acid,  treated  with  10  drops  of  very 
weak  bromine- water  or  of  fresh  chlorine- water,  and  then  with  2 
drops  of  ammonia-water:  but  with  0.0005  gram,  in  5  c.c.,  2  drops 

JFor  more  minute  examination  see  STOKES,  1853;  H.  Morton,  1871; 
"  Watts's  Diet.,"  3,  634;  8,  1193. 


QUININE.  131 

weak  bromine -water  and  1  drop  ammonia-water,  the  limit  is 
readied.  TRIMBLE  (1877)  lias  used  the  reaction  for  a  colorome- 
tric  method,  and  prepared  a  standard  green  solution  by  propor- 
tions of  0.01  quinine  or  quinine  salt  in  5  c.c.  of  fresh  chlorine  - 
water,  adding  10  c.c.  of  ammonia-water  and  diluting  to  100  c.c. 
— If  the  green  ammoniacal  solution  be  just  neutralized  with  acid 
a  blue  tint  is  obtained,  and,  by  acidulating,  a  violet  to  red  color, 
returning  to  green  again  when  ammonia  is  added  in  excess.  If 
ferricyanide  of  potassium  be  added  after  the  chlorine  or  bro- 
mine addition  as  above,  and  then  ammonia  barely  enough  for  an 
alkaline  reaction,  a  red  color  is  obtained.  Froehde's  reagent, 
with  dry  quinine,  gives  a  slight  green  color  (DRAGENBORFF). — 
The  thalleioquin  test  of  quinine  is  shared  by  quinidine,  diquini- 
cine,  and  quinicine,  also  by  hydroquinine  and  hydroquinidine, 
but  not  by  cinchonidine  nor  cinchonine. 

The  alkali  hydrates  precipitate  quinine  from  solutions  of 
its  salts,  the  precipitate  becoming  slowly  crystalline  (see  $),  and 
being  quite  readily  soluble  in  excess  of  ammonia,  and  somewhat 
soluble  in  excess  of  ammonium  carbonate,  not  of  the  fixed  alkali 
hydrates,  or  only  very  slightly  by  potassa.  Tartaric  acid  pre- 
vents the  precipitation  in  solutions  more  dilute  than  about  1  to 
300  ;  and  ammonium  chloride  increases  the  solubility  of  the  pre- 
cipitate.— In  free  ammonia  the  quinidine  and  cinchonidine  pre- 
cipitates are  less  soluble  than  that  of  quinine,  and  the  cinchonine 
precipitate  is  but  very  slightly  soluble. 

The  alkali  carbonates,  and,  more  slowly,  the  bicarbonates, 
precipitate  quinine,  insoluble  or,  with  bicarbonates,  but  slightly 
soluble  in  excess. 

Herapathite  test. — Herapathite  (HERAPATH,  1852)  is  one  of 
the  iodosulphates  of  quinine.  Its  formula  (JORGENSEN,  1876) 
is  (C?0H24N"2pa)4(H2SO4)3(HI)2I4.(H2O)n.  Dried  at  100°  C  ,  it 
contains  55.055  per  cent,  anhydrous  quinine.  It  crystallizes  in 
plates,  either  rectangular  or  rhombic,  of  six  or  eight  sides.  By 
reflected  light  the  crystals  are  very  lustrous,  or  iridescent  emerald- 
green  ;  by  transmitted  light  they  are  dichroic,  in  the  direction 
of  one  axis  nearly  transparent,  but  when  certain  axes  are  super- 
imposed they  are  nearly  opaque.  A  play  of  dark  and  light  shades 
is  obtained  with  crystals  of  microscopic  size  floating  in  a  drop  of 
liquid  undei?  the  cover-glass.  The  large  crystals  have  the  optical 
powers  of  tourmalines,  but  in  greater  intensity.  Herapathite  is 
at  first  nearly  insoluble  in  cold  water  and  soluble  in  1000  parts 
hot  water,  but  is  decomposed  by  water  with  formation  of  quinine 
bisulphate  and  hydriodide.  It  dissolves  in  50  parts  boiling  alco- 
hol of  85$  by  weight;  in  650  parts  of  cold  alcohol  of  same 


1  32  CINCHONA   ALKALOIDS. 

strength.  In  800  parts  of  90$  alcohol  at  10°  C. 
In  751  parts  of  92$  alcohol  at  24.5°  C.  (76.1°  F.)  (L>E  YKIJ,  1875). 
It  is  always  crystallized  from  alcohol,  usually  acidulated.  The 
large  crystals  of  herapathite  can  be  mechanically  separated  from 
amorphous  precipitate  of  other  cinchona  alkaloids. 

DE  YKIJ  states  (1882)  that  the  best  reagent  for  the  quali- 
tative recognition  of  crystallizable  quinine,  when  in  a  mixture 
of  cinchona  alkaloids,  is  the  iodosulphate  of  chinoidine,  pre- 
pared as  directed  (under  f)  for  quantitative  uses.  This  is  added 
to  a  solution  of  1  part  of  cinchona  alkaloids  dissolved  in  20 
parts  of  92-95$  alcohol  acidulated  with  1.5$  of  sulphuric  acid, 
this  solution  being  then  diluted  with  50  parts  of  alcohol.  The 
iodosulphate  reagent  is  added  (before  heating)  so  long  as  a  dark 
brown-red  precipitate  is  formed,  when,  with  slight  excess  of 
reagent,  the  liquid  acquires  a  yellow  color.  The  mixture  is  now 
heated  to  boiling,  to  dissolve  the  precipitate^  then  set  aside  for 
crystallization  of  the  herapathite.  BAKFOED  (1881)  dissolves  alka- 
loid supposed  to  contain  0.01  gram  quinine  in  20  drops,  or  0.01 
gram  quinine  sulphate  in  10  drops,  of  a  mixture  of  25  drops  of 
alcohol,  30  drops  of  acetic  acid,  and  1  drop  of  diluted  sulphuric 
acid,  heating  to  boiling,  and  then  adding  2  drops  of  alcoholic 
solution  of  iodine  (1  to  200)  and  setting  aside.  Crystallization 
may  begin  in  15  to  30  minutes. 

Excess  of  iodine  tends  to  produce  other  iodosulphates  of 
quinine.  JORGENSEN  (1876)  describes  three  classes  of  these  : 


C20H24N202)2(H2S04)  (HIU 
C20H24N203)3(H2S04) 


Olive-gray,  bronze,  brown,  blue,  and  black  colors  are  found, 
as  well  as  green  shades;  and  needles,  as  well  as  plates.  The 
results  are  governed  mainly  by  the  proportions  of  quinine,  io- 
dine, and  sulphuric  acid  taken.  The  other  cinchona  alkaloids 
form  iodosulphate  precipitates,  somewhat  more  soluble  in  alco- 
hol, and  less  crystallizable,  than  quinine  iodosulphate.  CHKISTEN- 
SEN  (1881)  states  that  cinchonidine,  if  present  in  at  all  large 
quantity,  may  be  precipitated  even  by  De  Yrij's  method  with 
chinoidine.  See  also  Cinchonine,  d.  Further  citations  from 
DE  YKIJ  are  given  under  /,  "  Quantitative"  p.  136. 

General  reagents  for  alkaloids.—  Potassium  mercuric  iodide, 
or  Mayer's  solution,  precipitates  quinine  in  white  flakes,  appear- 
ing in  acidulous  solutions  containing  loss  than  I  part  of  the  alka- 
loid in  100000  (/,  p.  136).—  Phosphomolybdate  throws  down 
quinine  from  acidulous  solutions,  the  yellow-  white,  curdy  preci- 


QUININE.  133 

pitate  being  almost  absolutely  insoluble.1 — Iodine  in  potassium 
iodide  solution  causes  a  reddish- brown  precipitate.  In  solutions 
other  than  that  of  the  sulphate  the  precipitate  is  at  first  soft 
or  amorphous  ;  in  presence  of  sulphuric  acid  the  precipitate  ap- 
proaches to  the  composition  and  appearance  of  herapathite.  See 
Cinchonine,  d. — Platinic  chloride,  in  solutions  not  very  dilute, 
a  bright  yellow  precipitate,  C20H24N2O2(HCl)2PtCl4 ,  soluble  in 
1500  parts  of  cold  water  or  in  2000  parts  of  boiling  alcohol.— 
Tannic  acid,  a  yellow- white  amorphous  precipitate  (see  p.  48), 
easily  soluble  in  warm  hydrochloric  acid. — Picric  acid,  in  satu- 
rated aqueous  solution,  a  yellow  amorphous  precipitate,  soluble 
in  alcohol,  from  which  it  crystallizes. — Potassium  sulphocyanate, 
in  concentrated  solutions,  a  white  precipitate,  more  soluble  than 
the  sulphate  (HESSE),  used  in  microchemical  examination,  p.  101. 
— Sulphates  give  a  precipitate  in  neutral  solutions  of  hydro- 
chloride  and  hydrobrornide  of  quinine,  if  not  diluted  to  the  ex- 
tent of  the  solubility  of  quinine  sulphate. — Concentrated  sul- 
phuric acid  causes  no  color;  Froehde's  reagent  a  greenish 
color. 

Potassium  iodide,  in  neutral  solutions  moderately  dilute, 
does  not  precipitate  quinine  salts  (separation  from  quinidine). 
A  saturated  solution  of  quinine  sulphate  is  not  affected.  The 
slightest  acidulation,  such  as  may  take  place  in  the  stomach,  may 
result  in  the  liberation  of  iodine  and  the  formation  of  insoluble 
quinine  iodides  resembling  herapathite. — Normal  tartrates,  as 
potassium  sodium  tartrate,  precipitate  moderately  concentrated 
solutions  of  quinine  salts,  the  normal  tartrate  of  quinine  being  a 
little  more  soluble  (c)  than  that  of  cinchonidine,  and  much  less 
soluble  than  those  of  quinidine  and  cinchonine  (to  be  observed  in 
cinchonidine  separation  by  tartrate). 

e. — Separations. — All  the  cinchona  alkaloids,  in  aqueous  solu- 
tions of  their  salts,  or  other  solutions  of  free  alkaloid,  are  evapo- 
rated to  dryness  at  100°-125°  C.  without  loss. — From  substances 
insoluble  in  ether,  chloroform,  or  amyl  alcohol,  quinine  is  sepa- 
rated by  action  of  these  solvents,  none  of  which  dissolves  salts  of 
quinine,  except  chloroform  very  slightly.  Benzene  in  sufficient 
quantity  dissolves  quinine,  as  does  aqueous  ammonia.  Methods 
of  separation  of  quinine  from  Cinchona  Bark  are  given,  pp.  102 
to  111;  from  other  Cinchona  Alkaloids,  index  at  p.  111.  From 
Morphine  and  from  Strychnine  quinine  is  pretty  nearly  sepa- 
rated by  its  solubility  in  ether,  less  fully  separated  by  its  solu- 
bility in  ammonia.  In  the  sulphates  quinine  is  approximately 

'The  author,  1877:  Am,.  Jour.  Phar.,  49,  483. 


134  CINCHONA    ALKALOIDS. 

separated  from  Morphine  and  from  Atropine  by  the  differences 
of  solubility  in  water.  From  Salicin  it  is  well  separated,  as  free 
alkaloid,  by  its  insolubility  in  water. 

From  Citrate  of  Iron  and  Quinine. — The  assay  method  of 
the  U.  S.  Ph.  is  as  follows :  "  The  salt  contains  12  per  cent,  of 
dry  quinine.  It  may  be  assayed  as  follows :  Dissolve  4  grams  of 
the  scales  in  30  c.c.  of  water,  in  a  capsule,  with  the  aid  of  heat. 
Cool,  and  transfer  the  solution  to  a  glass  separator,  rinsing  the 
capsule ;  add  an  aqueous  solution  of  0. 5  gram  of  tartaric  acid, 
and  then  solution  of  soda  in  decided  excess.  Extract  the  alka- 
loid by  agitating  the  mixture  with  four  successive  portions  of 
chloroform,  each  of  15  c.c.  Separate  the  chloroformic  layers, 
mix  them,  evaporate  them  in  a  weighed  capsule,  on  the  water- 
bath,  and  dry  the  residue  at  a  temperature  of  100°  C.  (212°  F.) 
It  should  weigh  0.48  gram." — The  Br.  Ph.  process  is  as  follows: 
"  Fifty  grains  [or  4  grams]  dissolved  in  a  fluid-ounce  [or  35  c.c.] 
of  water  and  treated  with  a  slight  excess  of  ammonia  gives  a 
white  precipitate,  which,  when  dissolved  out  by  successive  treat- 
ments of  the  fluid  with  ether  or  chloroform,  and  the  latter  evapo- 
rated, and  the  residue  dried  until  it  ceases  to  lose  weight,  weighs 
eight  grains  [or  0.639  gram]." — Mr.  J.  C.  FALK'  advises  to  add 
1  gram  of  tartaric  acid  in  the  U.  S.  Ph.  process,  as  he  found  the 
0.5  gram  insufficient  to  keep  the  iron  in  perfect  solution.  The 
four  portions  of  chloroform  are  often  insufficient.  The  solvent 
should  be  applied  till  a  portion  ceases  to  give  test  for  quinine. 
Analysts  often  find  it  difficult  to  recover  the  entire  quantity 
added.  The  use  of  a  continuous  extraction-apparatus  for  liquids 
is  desirable.  Mr.  Falk  recovered  11.925  from  the  addition  of  12. 
The  recovered  alkaloid  is  tested  most  readily  by  solubility  in 
ether,  more  certainly  by  the  application  of  the  Ammonia  Test  to 
free  alkaloid  (p.  139). 

Where  the  ammonia  test  is  the  official  standard  for  quinine 
hydrate  and  its  several  salts,  it  is  the  just  and  indisputable  stan- 
dard for  the  alkaloid  obtained  from  all  preparations  of  quinine, 
such  as  pills,  scales,  elixirs,  etc. 

Of  34  samples  of  citrate  of  iron  and  quinine  assayed  by  Dr. 
DAVENPORT,  State  Analyst  of  Drugs  in  Massachusetts,2  by  the 
U.  S.  Ph.  method,  85  per  cent,  fell  below  the  pharmacopoeial 
requirement,  though  the  greater  proportion  were  not  in  the  phar- 
macopoeial form  of  the  preparation. 

From  Coated  Pills  of  Quinine  Salts. — The  following  method 

1  1884:  Am.  Jour.  Phar.,  56,  316. 

2  "  Fifth  Annual  Report    State  Board  of    Health,"  etc.,   Mass.,   1884, 
p.  162. 


QUININE.  135 

contributed  by  HENRY  B.  PARSONS,'  and  verified  by  use  in  his 
constant  practice,  is  confidently  recommended :  Take  a  sufficient 
number  of  pills  to  represent  20  or  40  grains  of  sulphate  of  qui- 
nine ; a  treat,  in  a  very  small  Wedgewood  mortar,  with  5  c.c.  cold 
water  until  the  coating  dissolves  and  a  smooth  and  uniform  paste 
is  obtained ;  add  2  grams  (31  grains)  of  freshly  slaked  lime  in 
powder ;  mix  thoroughly  and  dry  the  mixture  slowly  in  the  mor- 
tar by  a  steam  or  water  bath.  The  dry  mass  is  to  be  finely  pow- 
dered and  transferred 3  to  a  Tollens  apparatus  for  continuous 
percolation,4  and  thoroughly  extracted  with  stronger  ether.  Eva- 
porate the  ethereal  solution  in  a  weighed  flask,  dry  for  one  hour 
at  125°  C.,  and  weigh  as  anhydrous  quinine.  Grams  of  anhy- 
drous quinine  X  20.7673  =  grains  of  quinine  sulphate  (7H2O). 

f. — Quantitative.  Gravimetric  estimation  as  free  alkaloid. — 
Quinine  is  frequently  estimated  by  weighing  the  residue  from  a 
solution  of  the  separated  alkaloid  in  ether,  chloroform,  or  amyl 
alcohol — a  method  without  objection  (see  0,  p.  134).  The  residue 
is  preferably  dried  first  at  a  very  moderate  heat  or  over  sulphuric 
acid  to  avoid  melting  (a),  and  finally  at  about  120°  C.,  arid  cooled 
in  a  desiccator.  The  objection  to  precipitation  for  weight  is 
the  loss  by  solubility  in  water.  Sodium  hydrate  is  without  ob- 
jection as  a  precipitant.  In  precipitating  quinine  sulphate  aci- 
dulate solution  with  sodium  hydrate,  and  washing  on  the  filter 
until  the  washings  gave  no  cloudiness  with  barium  chloride,  a 
loss  of  11.6  per  cent,  of  the  quinine  was  sustained.  The  solu- 
bility in  sodium  sulphate  solution  is  about  the  same  as  that 
in  pure  water.  Dry  quinine,  washed  on  the  filter,  ordinarily 
loses  about  0.0002  gram  per  c.c.  of  wash- water;  but  a  watery 
filtrate  fully  saturated  with  quinine  will  contain  about  0.0006 

1 1883:  New  Rem.,  12,  67;  Proc.  Am.  Pharm.,  31,  270. 

2  The  smaller  number  is  sufficient  if  manipulations  are  made  with  care  and 
the  balance  is  sensitive  to  tenths-milligram. 

3  By  use  of  a  small  steel  spatula.     The  mortar  then  rinsed  with  a  little  of 
the  ether. 

4  In  absence  of  a  Tollens  apparatus  good  results  may  be  obtained  by  a  very 
careful  operation  on  an  aliquot  part  of  the  solution  as  follows  :     Transfer  the 
dry  mass  to  a  small,  flat-bottomed  flask;  measure  in  an  exactly  taken  volume  of 
stronger  ether,  [stopper,  and  weigh]  and  agitate  the  stoppered  vessel,  occasion- 
ally, while  it  stands  for  12  hours  or  more.    [Weigh  again  and  add  ether  to  restore 
the  loss  if  any  has  occurred.]     By  use  of  a  pipette  measuring  accurately  [and 
agreeing  with  the  measure  by  which  the  ether  was  taken],  take  off  from  the  clear 
ethereal  solution  an  aliquot  part  by  volume  of  the  ether  taken,  and  evaporate  as 
directed  for  the  percolate. 

Chloroform  does  not  work  as  well  as  ether  as  a  solvent. — With  a  faithful 
execution  of  the  process  the  loss  is  not  over  |  per  cent. — In  answer  to  the  opi- 
nion of  MASSE  (1885)  that  quinine  suffers  loss  by  action  of  lime  at  100°  C.,  see 
PASSMORE  (1885). 


136  CINCHONA    ALKALOIDS. 

gram  per  c.c.  of  the  liquid  (c).1  The  precipitate  is  preferably 
dried  first  at  a  gentle  heat,  and  at  last  at  about  120°  C.  (248°  F.), 
as  the  last  molecule  of  water  is  difficult  to  expel  at  100°  C. 
Heat  to  about  170°  C.  is  borne  without  loss  of  alkaloid.  The 
dried  alkaloid  must  be  cooled  in  a  good  desiccator,  as  it  readily 
acquires  water  from  the  air. 

Gravimetric  determination  as  crystallized  sulphate,  dried 
at  100°  C.  (or  115°  C.)  to  anhydrous  sulphate,  or  at  60°  C.  to- 
effloresced  sulphate  (2H2O),  is  directed  under  Separation  of  Cin- 
chona Alkaloids,  p.  113. 

Gravimetric  determination  as  quinine  mercuric  iodide  by 
precipitation  of  the  acidulated  solution  of  the  sulphate,  with 
Mayer's  solution,  gives  fair  results.  The  precipitate  is  washed,  and 
dried  at  100°  C.,  when  2.900  grams  indicate  1.000  gram  of  quinine 
(as  dried  at  100°  C.)2  The  composition  of  the  precipitate  is  per- 
haps liable  to  variation  by  action  of  solvents,  bat  it  is  almost  in- 
soluble in  water. — The  precipitate  by  phosphomolybdate,  in  acid- 
ulated solution,  may  be  washed,  dried  below  70°  C..  and  weighed,, 
when  1  gram  of  quinine  is  represented  by  about  3.665  grams  of 
the  precipitate,3  the  result  being  properly  controlled  by  a  par- 
allel operation  upon  a  known  quantity  of  pure  quinine. 

Volumetric  estimationby Mayer '#  Solution. — The  precipitate,, 
as  stated  under  d  (p.  132),  has  very  little  solubility,  but  its  com- 
position is  probably  varied  by  conditions  of  temperature,  etc. 
According  to  Mayer,  in  dilution  of  1  to  800,  1  c.c.  of  the  re- 
agent =  0.0108  gram  of  anhydrous  quinine.4  It  is  advisable  to> 
control  the  results  by  a  parallel  titration  of  a  solution  of  quinine 
of  known  strength. 

Estimation  in  herapathite  (DE  YRIJ,  1882).  Preparation 
of  the  Reagent,  lodosulphate  of  Chinoidine. — Of  commercial 
chinoidine  1  part  is  heated  on  the  water -bath  with  two  parts  of 
benzene,  whereby  the  chinoidine  is  partly  dissolved.  The  clear,, 
cold  benzene  solution  is  shaken  with  an  excess  of  weak  sulphuric 
acid,  whereby  a  watery  solution  of  acid  sulphate  of  chinoidine  is- 
obtained.  After  ascertaining  in  a  small  part  of  this  solution  the 
amount  of  amorphous  alkaloid  contained  in  it,  so  that  its  whole 

1  " Laboratory  Notes,"  by  the  author,  1877:  Am.   Jour.  Phar.,  49,  481; 
Jour.  Chem.  Soc.,  32,  933;  Jahr.  Phar.,  1877,  419. 

2  "Laboratory  Notes,"  by  the  author,  1877  (where  last  cited). 

3  Last  citation. 

4BLYTH,  1881:  The  Analyst,  6,  161;  New  Rem.,  II,  34;  Proc.  Am.  Phar.r 
30,  410;  Jour.  Chem.  Soc.,  40,  1176.  The  factor  0.0108=1  of  ^J^r  of  the  m°- 
lecular  weight,  and  indicates  the  formula  (C2oH24N2O2)2(HI)x,  (HgI2)3  for  the 
precipitate,  but  this  is  not  supported  by  the  gravimetric  results  (A.  B.  PRESCOTT,. 
1880:  Am.  Chem.  Jour.,  2,  294;  Chem.  News,  45,  114). 


QUININE.  137 

quantity  in  the  solution  may  be  known,  the  clear  solution  is 
poured  into  a  large  capsule.  For  every  two  parts  of  amorphous 
alkaloid  contained  in  the  solution  1  part  of  iodine  and  2  parts 
of  iodide  of  potassium  are  dissolved  in  water.  This  solution  is 
slowly  added  with  continuous  stirring  to  the  liquid  in  the  cap- 
sule, so  that  no  part  of  it  comes  in  contact  with  an  excess  of 
iodine.  By  this  addition  there  is  formed  an  orange- colored, 
flocculent  precipitate  of  iodosulphate  of  chinoidiiie,  which,  either 
spontaneously  or  by  a  slight  elevation  of  temperature,  collapses 
into  a  dark  brown-red  colored  resinous  substance,  whilst  the 
supernatent  liquor  becomes  clear  and  slightly  yellow-colored. 
This  liquor — which,  if  the  direction  is  strictly  followed,  must 
still  contain  some  amorphous  alkaloid  as  a  proof  that  no  excess 
of  iodine  has  been  used — is  poured  oft',  and  the  resinous  sub- 
stance is  washed  by  heating  it  on  a  water-bath  with  distilled 
water.  After  washing,  the  resinous  substance  is  heated  on  a 
water- bath  till  all  water  has  been  evaporated.  It  is  then  soft 
and  tenacious  at  the  temperature  of  the  water-bath,  but  becomes 
hard  and  brittle  after  cooling.  One  part  of  this  substance  is 
now  heated  with  6  parts  of  alcohol  of  92  to  95  per  cent,  on  a 
water-bath,  and  is  thus  dissolved,  and  the  solution  allowed  to 
cool.  In  cooling,  a  part  of  the  dissolved  substance  is  separated. 
The  clear  dark  brown-red  colored  solution  is  evaporated  on  a 
water- bath,  and  the  residue  dissolved  in  5  parts  of  cold  alco- 
hol. This  second  solution  leaves  a  small  part  of  insoluble  sub- 
stance. The  clear  dark  brown-red  colored  solution  obtained  by 
the  separation  of  this  insoluble  matter,  either  by  decantation  or 
filtration,  constitutes  the  reagent  which,  under  the  name  of  "  iodo- 
sulphate of  chinoidine,"  Dr.  De  Vrij  uses  both  for  qualitative 
and  quantitative  determination  of  the  crystallizable  quinine  in 
barks. 

The  formation  of  herapathite,  in  the  estimation,  is  directed 
by  De  Yrij  as  follows :  Of  the  mixed  alkaloids  from  a  cinchona 
bark,  1  part  (1  gram  being  sufficient)  is  dissolved  in  20  parts  of 
alcohol  of  92  to  95  per  cent.,  containing  1.5  per  cent,  of  sulphuric 
acid  (of  which  an  excess  above  that  for  production  of  acid  sul- 
phates is  avoided).  The  resulting  alcoholic  solution  of  the  acid 
sulphates  of  the  alkaloids  is  then  diluted  with  50  parts  of  pure 
alcohol.  From  the  dilute  solution  so  obtained  the  quinine  is 
precipitated  at  the  ordinary  temperature  by  adding  carefully, 
by  means  of  a  pipette,  the  above-mentioned  solution  of  iodosul- 
phate of  chinoidine  as  long  as  a  dark  brown-red  precipitate  of 
iodosulphate  of  quinine  (herapathite)  is  formed.  As  soon  'as  all 
the  quinine  has  been  precipitated,  and  a  slight  excess  of  the  re- 


138  CINCHONA   ALKALOIDS. 

agent  has  been  added,  the  liquor  acquires  an  intense  yellow  color.1 
The  beaker  containing  the  liquor  with  the  precipitate  is  now 
covered  by  a  watch-glass,  and  heated  till  the  liquid  begins  to  boil 
and  all  the  precipitate  is  dissolved.  The  beaker  is  then  left  to 
itself,  and  in  cooling  the  herapathite  is  separated  in  the  well- 
known  beautiful  crystals.  After  twelve  hours'  rest  [finally  at 
16°  C.]  the  beaker  is  weighed  to  ascertain  the  amount  of  liquid 
which  is  necessary  in  order  to  be  able  to  apply  later  the  neces- 
sary correction;  for  although  the  quinine-herapathite  is  very 
slightly  soluble  in  cold  alcohol,  it  is  not  insoluble  (d,  p.  131). 
It  is  ascertained  with  a  small  portion  of  the  solution  that 
enough  reagent  has  been  added,  when  the  clear  liquid  is  poured 
off,  as  far  as  possible,  on  a  filter,  leaving  the  majority  of  the 
crystals  in  the  beaker,  which  is  now  weighed  again  to  ascertain 
the  amount  of  liquid,  which  is  noted  down.  The  crystals  are 
now  dissolved  to  recrystallize,  for  removal  of  traces  of  adhering 
cinchonidine  iodosulphate,  as  follows :  The  crystals  on  the  filter 
are  washed  into  the  beaker  with  a  little  of  the  alcohol,  and  all 
the  crystals  dissolved  in  just  enough  alcohol  at  the  boiling  point. 
After  perfect  cooling  [and  standing  at  16°  C.]  the  weight  of 
the  beaker  is  taken,  the  crystals  carefully  collected  on  a  small 
filter,  and  the  empty  beaker  weighed  again.  The  difference  in 
weight  will  indicate  the  amount  of  liquor,  which  is  added  to 
that  of  the  first  liquor.  The  sum  of  the  weights  of  the  li- 
quor X  0.00125  =  correction  for  solubility  of  the  herapathite, 
provided  the  crystallization  has  been  completed  at  16°  C.2  The 
herapathite  crystals  on  the  filter  are  thoroughly  washed  with  a 
saturated  alcoholic  solution  of  pure  herapathite.3  The  washed 
crystals  are  drained,  with  tapping  of  the  side  of  the  funnel,  the 
filter  taken  out  and  quickly  pressed  between  blotting-papers, 
and  as  soon  as  air-dry  the  crystals  are  transferred  from  the  filter 
to  a  fitted  pair  of  watch-glasses,  and  dried  on  the  water-bath  (or 
at  100°  C.)  to  a  constant  weight,  avoiding  the  access  of  air.  To 
the  weight  is  added  the  correction  for  solubility,  to  obtain  the 
total  quinine  iodosulphate,  (C20II24N2O2)4(II2SO4)3(HI)2I4  (d, 

1  If  cinchonidine  be  present  in  large  quantity,  the  author  states  that  the 
due  control  of  this  slight  excess  of  the  reagent  requires  a  great  deal  of  practical 
experience,  and  must  be  studied  on  a  solution  of  cinchonidine  itself,  taken  in 
the  proportions  above  directed. 

2  If  another  temperature  has  been  employed,  the  solubility  of  the  hera- 
pathite is  to  be  determined  by  experiment  at  such  temperature.     In  this  the 
herapathite  can  be  estimated  by  volumetric  hyposulphite:  21.58  parts  of  iodine 
representing  100  parts  of  herapathite. 

3  A  washing-bottle  containing  an  excess  of  pure  crystallized  herapathite  in 
95  per  cent,  alcohol  may  be  kept  ready  for  application. 


QUININE.  139 

p.  132),  of  which  one  part  contains  0.55055  part  of  anhydrous 
quinine. 

g. — Tests  for  impurities  and  deficiencies. — The  impurities  or 
deficiencies  of  quinine  salts  to  be  generally  regarded  are,  in  or- 
der of  importance,  (1)  other  cinchona  alkaloids  in  excess  of  a 
proper  limit,  and  (2)  an  excess  or  deficiency  of  moisture  or  water 
of  crystallization,  causing  variableness  of  strength.  Quinine 
manufacture  is  mainly  conducted  by  a  small  number  of  houses 
of  well-known  standing,  and  the  product  is  carried  in  well-regu- 
lated commercial  channels,  so  that  it  is  but  little  exposed  to  the 
introduction  of  falsifications.  The  one  cinchona  alkaloid,  not 
quinine,  most  difficult  for  the  manufacturer  to  remove  and  for 
the  analyst  to  estimate,  and  actually  present  in  largest  proportion 
in  the  product  from  barks  in  general,  is  cinchonidine.  In  the  pro- 
duct of  the  "  cuprea  "  barks,  however,  another  alkaloid  is  intro- 
duced, which  is  cupreine,  or  the  conjugated  compound  of  cupreme 
with  quinine  known  as  homoquinine,  and  it  becomes  necessary 
to  give  general  attention  to  the  possible  presence  of  this  alkaloid. 

The  recognized  tests  for  other  cinchona  alkaloids  depend,  in 
principal,  upon  (1)  the  removal  of  quinine  as  a  crystallized  sul- 
phate (KEENER,  1862),  (2)  the  separation  of  the  free  alkaloids  by 
ether  (Liebig's  test),  or  (3)  by  excess  of  ammonia  (KEKNEK, 
1862),  which  is  used  also  in  all  tests  to  liberate  the  alkaloids  from 
their  salts.  Hesse's  test  (1879)  depends  upon  principles  (1)  and 
(2),  as  also  does  Paul's  (1877),  while  Kerner's  test  depends  upon 
(1)  and  (3). 

Kernels  test  of  Quinine  Sulphate  provides  a  uniform  arbi- 
trary measure,  by  certain  fixed  conditions,  as  follows  :  Quinine  as 
a  sulphate  is  macerated  with  water;  the  quantity  of  the  water  is 
10  parts  for  1  part  of  crystallized  sulphate  ;  at  whatever  tempera- 
ture the  maceration  is  commenced,  it  is  invariably  concluded  at 
the  temperature  of  15°  C.,  when  the  mixture  is  at  once  filtered ; 
and  of  the  filtrate  5  c.c.  (for  some  purposes  10  c.c.)  are  treated 
with  an  accurately  measured  volume  of  ammonia-water  of  exact- 
ly known  strength  (s.g.  0.920  or  0.960)  until  a  clear  liquid^is  ob- 
tained, the  ammonia- water  being  mixed  at  once  with  the  filtrate 
by  gently  inclining  or  rotating  the  test-tube  while  this  is  closed 
with  the  finger.— With  a  small  and  not  bibulous  filter  1  gram  of 
crystallized  sulphate  with  10  c.c.  of  water  will  easily  yield  the 
5  c.c.  of  filtrate  for  one  ammonia  test.  Directions  often  specify 
2  grams  of  the  crystals  with  20  c  c.  of  water;  and  for  quantita- 
tive titrations  it  becomes  proper  to  take  5  grams  of  the  crystal- 
lized sulphate  with  the  tenfold  number  of  c.c.  of  water,  to  pro- 


HO  CINCHONA   ALKALOIDS. 

vide  for  several  parallel  ammonia  tests;1  but  it  will  be  observed 
that  the  required  quantity  of  ammonia,  the  index  of  the  test,  is 
only  placed  in  ratio  to  the  5  or  10  c.c.  of  the  filtrate  [where  it  acts 
not  wholly  independent  of  variations  of  atmospheric  temperature], 
and  has  no  ratio  to  the  quantity  of  quinine  sulphate  taken.  It 
will  be  further  observed  that  the  fixed  proportion  of  water  taken 
in  maceration,  10  parts  to  1  of  the  salt,  controls  the  quantity  and 
concentration  of  the  alkaloids  not  quinine.  The  10  parts  of 
water  at  15°  C.  would  dissolve  0.1  part  of  cinchonidine,  10$  of 
the  quinine  sulphate  taken,  and  a  smaller  quantity  of  water 
would  in  most  cases  dissolve  the  entire  quantity  of  alkaloids  not 
quinine,  but  it  is  of  importance  that  the  solution  of  these  alka- 
loids shall  be  made  up  to  the  same  volume  in  every  trial  of  the 
test.  vThe  quinine  sulphate  is  in  excess  of  saturation  of  this  salt ; 
indeed,  one-fiftieth  as  much  quinine  salt  would  suffice  to  more 
than  saturate  the  10  parts  of  water. — In  Kerner's  method  the 
Quinine  Sulphate  is  readily  recovered  in  purified  form,  almost 
without  waste,  and  sometimes  with  gain,  of  value.  Of  the  real 
quinine  sulphate  99.86$  remains  on  the  filter  as  Recrystalli zed 
Sulphate  of  Quinine.  It  is  dried  by  pressing  gently  between 
blotting-papers  and  setting  aside  in  dry  air,  avoiding  efflorescence. 
The  quinine  dissolved  by  the  ammonia  crystallizes  on  evapora- 
tion of  the  latter,  and  this  separation  has  been  adopted  in  puri- 
fying small  quantities  of  quinine. 

For  5  c.c.  of  aqueous  solution  saturated  at  15°  C.  the  volumes 
of  ammonia-water  of  sp.  gr.  0.92  (21.7$  NH3),  and  of  sp.  gr. 
0.96  (10$  NH3),  required  to  give  a  clear  solution,  are  as  follows 
(KERNEB,  1880 2) : 

1  HAGER  arranges  for  special  tests,  in  different  portions  of  the  filtrate,  for 
single  cinchona  alkaloids,  but  of  these  special  tests  the  only  trusty  one  is  that 
for  quinidine,  rarely  present — a  test  made  with  5  c.c.  of  the  nitrate  by  adding 
5  drops  of  a  1  to  20  solution  of  potassium  iodide,  stirring,  and  setting  aside  for 
crystallization  of  quinidine  hydriodide. 

2  Archiv  d.  Phar..  [3],  17,  444.     In  these  experiments  with  alkaloids  other 
than  quinine  they  were  sometimes  added  (in  known  quantity  of  their  sulphates) 
to  the  5  c.c.  of  the  filtrate  from  pure  quinine  sulphate,  but  in  case  of  cinchoni- 
dine it  was  mixed  with  the  crystallized  pure  quinine  sulphate  for  one  series  of 
trials,  and  in  certain  of  the  tests  there  was  maceration  with  water  at  60°  and  at 
80°  C.  before  the  crystallization  at  15°  C.     These  varied  conditions  made  little 
difference  with  the  results.     But  when  the  quinine  and  cinchonidine  sulphates 
have  been  crystallized  together,  previous  hot  digestion  increases  the  efficiency 
of  the  separation.     See  YUNGFLEISCH,  1887:  P/iar.  Jour.   Trans.  [8]  17,  585; 
Jour,  de  Pharm.  [5]  25,  5.     The  same  is  stated  in  general  terms  by  PAUL  1877: 
Phar.  Jour.  Trans.  [3]  7,  654.     The  author   is   indebted  to  E.  A.  RUDDIMAN 
for  determinations  of  difference  due  to  previous  hot  digestion,  a  report  of  which, 
will  soon  be  presented  for  publication. 


QUININE. 


141 


With  pure  Quinine 
Sulphate  

Ammonia  ofs.g.0.  960. 
5.0  to  5.3  c.c. 

Ammonia  of  s.g.  0.920.1 
3.0  to  3.3  c.c. 

For  0.001  gram  Cin- 
chonidine        sul- 
phate added  .... 
For  each  per  cent, 
of    Cinchonidine 
sulphate.   . 

Additional  to  above. 

0.40  c.c.  to  0.44  c.c. 
2.0  e.c.  to  2.  2  c.c. 

Additional  to  above. 
0.28  to  0.35  (av.  0.32)  c.c. 
1.4  to  1.7  (w.  1.6)  c.c. 

For     0.001     gram 
Quinidine       sul- 
phate   

1.16  c.c.  to  1.34  c.c. 

0.56  c.c.  to  0.78  c.c. 

For  1  per  cent.  Qui- 
nidine sulphate.  . 
For      0.001     gram 
Cinchonine     sul- 
phate 2  

5.8  c.c.  to  6.7  c.c. 
0.62  c.c.  to  0.80  c.c. 

2.8  c.c.  to  3.9.  c.c. 
0.36  c.c.  to  0.40  c.c. 

For     1     per    cent. 
Cinchonine     sul- 
phate 

3.1  c.c.  to  4.0  c.c. 

1.8  c.c.  to  2.0  c.c. 

Kerner's  test,  in 
whether  the  article  t 

the  pharmacopoaial 
ested  does  or  does 

form,  merely  determines 
not  reach  a  certain  recog- 

nized  limit  of  impurity ;  but,  as  applied  by  the  analyst,  the  am- 
monia-water should  be  added  from  the  burette  and  the  required 
number  of  c.c.  should  be  noted,  as  an  index  of  the  degree  of 
impurity,  whether  above  or  below  the  legal  standard.  The 
number  of  c.c.  of  ammonia-water  (of  pharmacoposial  strength 
and  under  pharmacopoeial  conditions)  is  in  itself  a  certain  measure 
of  value,  already  having  a  meaning  to  dealers  and  consumers, 
irrespective  of  interpretations  in  per  cent,  of  cinchonidine  or 

1  Experiments  by  Mr.  E.  A.  RUDDIMAN,  made  in  an  investigation  now  in 
progress  in  the  University  of  Michigan,  Indicate  that  of  ammonia  water  of  s.  g. 
0.960  there  are  required  only  1.5  times  more  than  of  the  water  of  s.  g.  0.920, 
though  the  latter  is  2.2  times  stronger  than  the  former.  Averages  of  ten  titra- 
tions,  for  each  degree  between  15°  and  25°  C.,  agreed  nearly  with  this  ratio  of 
1.5  to  1.0. 

*  In  respect  to  cinchonine  (in  presence  of  much  quinine)  these  data  are  sur- 
prising. Taken  separately,  each  in  a  cold-saturated  sulphate  solution  (15°  C.), 
Kerner  in  1862  found  the  quantities  of  ammonia  used  to  redissolve  the  alkaloid 
from  1  c.c.  of  the  filtrate  as  follows:  Of  ammonia- water  of  s.g.  0.960,  for  qui- 
nine, 1.3  c.c. ;  for  cinchonidine,  16  c.c. ;  for  quinidine  (b  Quinidine).  15  c.c. ;  for 
cinchonine,  over  300  c.c. — The  experiments  made  by  Mr.  TEETER  (Univ.  Mich., 
1880:  New  Rem.,  g,  258)  in  defining  the  limits  of  the  test  of  quinine  sulphate 
only  show  that  in  the  preponderating  presence  of  quinine  both  quinidine  and 
ciuchonine  require  more  ammonia  than  cinchonidine  does. 


H2  CINCHONA    ALKALOIDS. 

other  alkaloids.  The  ammonia  measure,  based  upon  fixed  condL 
tions  of  application,  may  be  adopted  over  the  world  as  a  simple 
expression  of  comparative  value.  Against  this  preference  for 
the  ammonia  measure  it  can  hardly  be  urged  that  there  is  dis- 
agreement as  to  how  many  per  cent,  of  cinchonidine  are  ad- 
mitted under  7  c.c.  or  6£  c.c.  of  ammonia.  There  may  be  dis- 
agreement as  to  the  interpretation  of  any  method  of  valuation. 

Kernels  volumetric  estimation  of  cinchonidine  in  commer- 
cial quinine  sulphate  is  only  an  elaboration  of  his  limit-test,  so 
devised  that  the  result  is  verified  by  a  control  analysis  in  each 
operation.  It  is  as  follows  :  * 

Standard  Quinine  Sulphate  (Normalchininsulphat)  is  pre- 
pared by  recrystallizing  the  salt  from  hot  solution,  with  such  a 
slight  addition  of  sulphuric  acid  as  shall  give  a  faint  acid  reac- 
tion, usually  crystallizing  from  three  to  six  times,  and  until  two 
portions  of  a  crop  of  crystals,  macerated  at  about  15°  C.,  the  one 
in  10  parts  of  water  and  the  other  in  500  to  700  parts  of  water, 
in  parallel  conditions,  on  titration  of  10  c.c.  of  filtrate  with  am- 
monia-water, require  the  same  number  of  c.c.  of  ammonia  for 
solution.  Usually  by  the  recrystallizations  the  salt  becomes 
neutral  in  reaction. — The  Standard  Quinine  Sulphate  Solution 
is  prepared  freshly  for  use  by  rubbing  the  salt  with  about  100 
times  its  weight  of  water  in  a  mortar,  rinsing  into  a  glass-stop 
pered  bottle,2  and  digesting  along  with  the  commercial  quinine 
sulphate  to  be  estimated,  in  the  same  conditions  of  temperature 
and  time,  as  directed  below. — Water  of  Ammonia  of  sp.  gr.  0.920 
of  ordinary  quality  is  all  that  is  required  as  a  reagent. —  In  the 
titration  5  grams  of  the  sulphate  of  quinine  to  be  tested  are 
rubbed  in  a  mortar  with  distilled  water  enough,  so  that  when  all 
is  rinsed  into  a  glass-stoppered  bottle  it  shall  just  reach  a  mark 
of  50  c.c.  volume.  This  bottle  and  the  bottle  containing  the 
standard  quinine  sulphate  solution  are  now  set  in  the  same  ves- 
sel of  cold  water,  at  as  near  15°  C.  as  convenient,  and  left,  with 
occasional  careful  shaking,  for  12  to  18  hours.  Or  both  bottles 
are  warmed  in  the  same  vessel  of  water  at  near  100°  C.  for  some 
time,  shaking  several  times,  and  then  set  together  in  a  vessel  of 
cold  water  for  an  hour  or  more.  The  bottle  containing  the  am- 
monia is  placed  in  the  same  cold  water,  so  that  at  the  end  of  the 

JKERNEE,  1862.  Improved  in  1880:  Archiv  d.  Phar.,  [3],  16,  186-285; 
17,  438-454;  Jour.  Chem.  Soc.,  40,  63;  New  Rem.,  10,  168. 

2  The  standard  quinine  solution  should  be  strictly  neutral  in  reaction.  If 
acidulous,  it  is  to  be  brought  back  to  the  neutral  point  by  adding  to  it,  with 
agitation,  just  sufficient  of  quinine  hydrate,  freshly  precipitated  from  the  same 
solution  and  well  washed. — A.  B.  P. 


QUININE.  143 

digestion  it  shall  have  the  same  temperature.  The  two  quinine 
solutions  are  now  filtered  through  two  dry  filters,1  at  the  ordi- 
nary atmospheric  temperature  (which  is  preferably  near  that  of 
the  digestion),  obtaining  from  the  standard  quinine  solution  the 
same  volume  of  filtrate  furnished  by  the  other  solution  (40  c.c. 
or  over).  10  c.c.  of  each  of  these  solutions  is  taken,  by  a  good 
pipette,  in  a  test-tube  for  titration.  The  ammonia  is  added  from 
a  burette,  which  is  better  if  it  be  long,  and  narrow  enough  to 
register  in  -fa  c.c.  At  first  5  c.c.  of  the  ammonia  are  run  in,  the 
test-tube  closed  by  the  finger  and  given  two  or  three  circular 
motions  to  mix  the  liquid  without  shaking,  and  further  smaller 
additions  made,  0.3,  0.2,  0.1  c.c.,  and  by  drops,  with  the  circular 
agitation  after  each  addition,  until  the  liquid  becomes  perfectly 
clear.  Toward  the  last  it  is  well  to  wait  5  to  10  seconds  after 
each  agitation  before  the  next  addition.  The  end  reaction  is 
complete  clearing.  Then  at  once  the  standard  quinine  solution 
is  titrated  in  the  same  way,  taking  a  fresh  portion  of  ammonia 
in  the  burette.  The  40  c.c.  will  suffice  for  four  titrations  of 
each  quinine  solution,  from  which  the  average  can  be  taken. — • 
Each  0.32  c.c.  (or  0.3,  round  number,  the  extremes  being  0.28 
and  0.35  c.c.)  of  the  excess  of  the  ammonia  required  for  the  qui- 
nine under  test  (beyond  that  required  for  the  standard  quinine) 
indicates  0.001  gram  of  cinchonidine  sulphate.  This  0.001  gram 
of  cinchonidine  sulphate  is  estimated  upon  the  commercial  qui- 
nine salt  represented  by  the  (10  c.c.)  portion  of  filtrate  taken,,  or 
(having  taken  10  c.c.  of  a  1  :  10  solution)  each  0.32  c.c.  of  0.920 
ammonia  (beyond  that  taken  for  the  standard  sulphate)  indi- 
cates 0.1  per  cent,  of  the  cinchonidine  impurity. 

Should  the  percentage  of  cinchonidine  be  over  1. 5,  or  at  most 
2.0,  the  results  become  inaccurate,  owing  to  the  gelatinizing  of 
the  precipitated  alkaloid.  In  this  case  10  c.c.  of  the  filtrate 
under  estimation  may  be  diluted,  by  addition  of  standard  quinine 
filtrate  (of  parallel  digestion),  to  20,  30,  or  40  c.c.,  and  portions 
of  10  c.c.  of  this  diluted  filtrate  titrated.  Then,  after  deduct- 
ing the  average  c.c.  of  ammonia  taken  by  10  c.c.  of  standard 
quinine,  the  remaining  c.c.  are  multiplied  by  2,  or  3,  or  4, 
when  each  0.32  c.c.  =  0.1$  cinchonidine,  as  before.  The  errors 
are  stated  not  to  exceed  0.05  per  cent,  of  the  commercial  quinine 
salt. 

JThe  crystalline  residues  in  the  filters  are  to  be  saved,  as  purified  sulphate 
of  quinine,  drying  them  by  pressing  the  filters  between  blotting-papers,  etc. 
It  will  be  observed  that  the  residue  from  filtration  of  the  "standard  quinine 
sulphate"  solution  is  " standard  quinine  sulphate"  prepared  with  an  addi- 
tional purification. 


c44  CINCHONA    ALKALOIDS. 

A.n  approximate  volumetric  estimation  is  made  in  a  short 
operation,  according  to  Kerner  (where  last  quoted),  as  follows : 
The  quinine  salt  to  be  tested  is  macerated  with  ten  times  its 
weight  of  water  at  15°  0.,  5  c.c.  of  the  filtrate  is  taken  in  a  test- 
glass  of  10  c.c.  capacity  graduated  in  0.1  c.c.,  3  c.c.  of  water  of 
ammonia  of  sp.  gr.  0.920  are  added  and  intermixed  by  gentle 
circular  agitation  of  the  test-glass  while  covered  by  the  linger, 
and  additions  further  made,  at  last  by  drops,  until  a  clear  liquid 
is  attained,  when  the  total  volume  is  read  and  the  volume  of 
added  ammonia  is. noted. — The  required  addition  of  only  3.0  to 
3.3  c.c.  of  the  ammonia- water  would  indicate  absence  of  cincho- 
nidine  sulphate;  use  of  5  c.c.  ammonia  (0.920)  indicates  near  1 
per  cent,  cinchonidine  sulphate ;  and  these  data  serve  to  show 
approximately  the  indication  *  (Kerner). 

The  U.  8.  Ph.  (1880)  directions  for  Kernels  test  are  as  fol- 
lows :  '"  The  residue  of  1  gram  of  (crystallized)  sulphate  of  qui- 
nine, dried  to  a  constant  weight  at  100°  C.  for  estimation  of 
water,  is  agitated  with  10  c.c.  of  distilled  water,  the  mixture 
macerated  at  15°  C.  (59°  F.)  for  half  an  hour,  then  filtered  through 
a  small  filter,  5  c.c.  of  the  filtrate  taken  in  a  test-tube,  and  7  c.c. 
of  water  of  ammonia  (sp.  gr.  0.960)  then  added;  on  closing  the 
test-tube  with  the  finger,  and  gently  turning  it  until  the  ammonia 
is  fully  intermixed,  a  clear  liquid  should  bo  obtained.  If  the 
temperature  of  maceration  has  been  16°  C.  (60.8°  F.),  7.5  c.c.  of 
the  water  of  ammonia  may  be  added  ;  if  17°  C.  (62. 6°  F.),  8  c.c.a 
may  be  added.  In  each  instance  a  clear  liquid  indicates  the  ab- 
sence of  more  than  about  1  per  cent,  of  cinchonidine  3  or  quiiii- 
dine,  and  of  more  than  traces  of  cinchonine." 

The  Ph  Germ.  (1882)  directions  are  these :  2  grams  of 
quinine  sulphate  are  agitated  with  20  c.c.  of  water  at  15°  C., 
and  after  half  an  hour  filtered.  To  5  c.c.  in  a  test-tube  am- 
monia [0.960]  is  added  until  the  precipitated  quinine  is  again 
dissolved.  The  required  quantity  of  ammonia  should  not  overgo 
7  c.c. 

The  Ph.  Fran.  (1884)  directs  the  2  grams  quinine  sulphate 

1  By  a  more  minute  calculation,  if  the  ammonia- water  hold  its  strength, 
each  0.32  c.c.  added  above  about  3.3  c.c.  indicates  0.2  percent,  of  cinchonidine; 
so  that  1  per  cent,  of  cinchonidine  is  indicated  by  4.9  c.c.  (total  addition),  and 
2  per  cent,  by  6.5  c.c.     But  exactness  is  not  to  be  assumed  without  the  help  of 
the  control  analysis. — A.  B.  P. 

Differences  "of  0.5°  C.,  Kerner  states,  do  not  sensibly  affect  the  result. 

2  These  official  allowances  for  temperature  are  more  liberal  than  Kerner's 
results  would  justify. 

^See  the  table  from  Kerner's  figures,  p.  141,  according  to  which  (at  15°  C.) 
from  7.0  to  7.5  c.c.  are  required  for  1  per  cent,  of  cinchonidine  sulphate. 


QUININE.  145 

in  20  c.c.  of  water  to  be  digested  hot  for  half  an  hour,  then 
maintained  at  15°  C.  by  immersion  in  a  bath  of  water  of  this 
temperature  for  half  an  hour  with  frequent  agitation,  and  filtered. 
Of  the  filtrate,  5  c.c.  are  treated  with  7  c.c.  of  ammonia-water  of 
0.960  sp.  gr.,  when  a  precipitate  after  gentle  intermixture,  or  a 
turbidity  or  crystalline  deposit  formed  after  24  hours,  indicates 
an  unacceptable  proportion  of  alkaloids  other  than  quinine. 
Another  portion  of  5  c.c.  is  evaporated  in  a  tared  capsule  to  a 
weight  constant  at  100°  C.,  when  the  weight  of  the  residue  should 
not  exceed  0.015  gram.1 

Temperature  of  the  Filtrate  in  the  reaction  of  the  ammonia. 
— Hitherto  the  influence  of  temperature  has  been  regarded  only 
as  affecting  the  solubility  of  the  sulphate  of  quinine,  and  the 
concentration  of  this  salt  in  the  filtrate.  The  temperature  of 
digestion  has  been  regulated,  while  that  of  the  filtrate  and  the 
ammonia- water  has  been  left  to  vary  with  the  warmth  of  the 
atmosphere.  From  experiments  recently  made  by  Mr.  E.  A. 
Kuddiman,  in  the  laboratory  in  which  the  author  is  engaged,  it 
appears  that  the  temperature  of  the  filtrate  under  addition  of  the 
ammonia  is  influential.  With  digestion  and  filtration  at  15°  C., 
the  warmer  the  filtrate  becomes,  the  less  ammonia  is  required  to 
redissolve  the  quinine.  For  each  1°  C.  increase  of  temperature 
in  the  titration,  an  average  of  0.148  c.c.  less  of  ammonia  of  sp.  gr. 
0.920  is  required  to  redissolve  the  quinine.  This  average  was 
drawn  from  over  ten  titrations  for  each  degree  between  14°  C. 
and  26°  C.,  the  temperature  of  the  filtrate  being  taken  at  the  end 
of  the  titration,  the  filtration  itself  being  always  held  with  the 
digestion  at  15°  C.  The  extremes  were  0.1  and  0.2  c.c.,  for  1°  C. 
— 5n  volumetric  estimation  by  comparison  with  standard  quinine 
sulphate,  this  influence  of  temperature  of  titration  of  the  quinine 
will  be  the  same  in  each  of  the  parallel  operations,  and  there- 
fore will  not  vitiate  the  conclusion.  But  in  the  pharmacopoeial 
tests,  differences  of  titration  temperature  must  affect  the  result, 
in  part  counteracting  like  differences  of  temperature  in  the 
digestion. — The  effects  of  titraticn  temperature  upon  the  cin- 
chonidine,  cinchoriine,  and  quinidine  are  questions  under  in- 
vestigation. 

In  1884  Mr.  HENRY  B.  PARSONS  2  reported  the  application  of 
the  U.  S.  Ph.  form  of  the  test  to  1033  samples  of  quinine  sul- 


1  The  residue  of  pure  quinine  sulphate  would  be  0.00675,  leaving  0.00825  to 
consist  of  other  alkaloids  or  impurities— a  quantity  constituting  about  1.6  per 
cent,  of  the  commercial  quinine  sulphate  tested. 

5  "  The  Practicability  of  Kerner's  Test  ":  Proc.  Am.  Phar.,  32,  458. 


146  CINCHONA    ALKALOIDS. 

phate,  embracing  5  brands,  of  American,  German,  and  Italian 
production,  as  follows : 

Brand.  No.  samples.   Average  c.c.  Am.    Over  1  c.c.  Am. 

No.  1.  American.  16  9.5  16 

"  .  2.          "  217  5,7  1 

"  3.    German.  11  6.1  none 

"  4.          "  627  6.0  7 

"  5.     Italian.  162  6.8  35 


Total,          1033  6.1  c.c.  av.        59  (rejected). 

Mr.  Parsons  states  that  i '  if  the  sample  of  quinine  sulphate  be 
dried  before  testing,  as  the  U.  S.  Ph.  directs,  the  amount  of  am- 
monia-water required  to  produce  a  clear  solution  is  generally, 
but  not  always,  about  0.5  c.c.  greater  than  where  the  same  sample 
is  not  dried  before  testing."  Also,  "the  test  is  liable  to  mislead 
unless  every  detailed  precaution  is  observed." — In  1884  B.  F. 
DAVENPORT,  as  State  Analyst  of  Drugs  in  Massachusetts,1  ex~ 
amined  28  samples,  from  seven  makers,  using  the  official  form  of 
Kerner's  test,  and  found  -28  per  cent,  of  the  samples  to  fall  below 
the  U.  S.  Ph.  requirement. 

The  application  of  the  Ammonia  Test  to  Quinine  Com- 
pounds other  than  the  Sulphate  requires  their  conversion  into 
sulphate.2 — This  may  be  done,  in  an  exact  application  of  the  test 
to  salts  of  quinine*  other  than  sulphates,  very  easily  as  follows : 
A  weighed  quantity,  ^rom  2  to  5  grams,  of  the  salt  is  dissolved 
in  about  fifty  times  iid  weight  or  a  sufficient  quantity  of  water, 
the  alkaloids  completely  precipitated  with  sodium  hydrate  solu- 
tion, the  precipitate  washed  until  the  washings  give  but  little 
cloudiness  with  magnesium  salt  solution,  and  the  washed  preci- 
pitate rinsed  through  a  perforation  in  the  filter-point  into  a  test- 
glass,  graduated  in  \  c.c.  and  measuring  20  to  50  c.c.,  filling  to 
near  the  volume  specified  below.  The  mixture  is  heated  for 
five  minutes  by  immersing  the  test-glass  in  nearly  boiling  water, 


1  "  Fifth  Ann.  Report  Mass.  State  Board  of  Health,"  etc.,  Boston,  1884, 
p.  161. 

2  In  his  first  paper,  in  1862,  Kerner  proposed  to  apply  the  ammonia  test 
directly  to  salts  not  sulphate,  directing  the  solution  of  the  salt  to  be  diluted  to 
the  limit  of  solubility  of  quinine  sulphate  (Zeitsch.  anal.  Chem.,  I,  161).     The 
later  report  (1880)  does  not  reach  the  application  to  other  salts. 

3 To  find,  for  any  salt  of  quinine,  the  volume  equal  to  10  c.c.  for  each  gram 
of  crystallized  normal  sulphate  producible  from  1  gram  of  said  salt:  Comb.  no. 
of  salt  taken  (in  equation  to  form.  1  mol.  sulphate)  :  872  :  :  10  :  x  =  c.c.  de- 
sired. 


QUININE.  14; 

and  dilute  sulphuric  acid  is  added  to  maintain  a  slight  acid  re- 
action to  litmus-paper  during  the  digestion.  The  mixture  is 
now  exactly  neutralized  to  litmus-paper  by  adding  dilute'  am- 
monia-water, the  volume  of  the  whole  made  up  to  a  number 
of  c.c.  equal  to 

11.5  times  the  number  of  grams  of  quinine  hydrochloride  taken, 
10.3  "  "  "  hydrobromide  " 

9.8  "  "  "  valerianate  " 

when  the  mixture  is  placed  for  half  an  hour  or  longer  in  a  bucket 
of  water  at  15°  C.  (59°  F.),  and  filtered  through  a  small  filter.  One 
or  more  portions  of  5  c.c.  are  tested  with  ammonia-water,  as  in 
the  pharmacopoeial  form  of  the  test  (see  page  144),  and  the  result 
judged  for  the  salt  taken,  on  the  basis  of  quinine  sulphate.  Or, 
cooling  parallel  with  "  standard  quinine  sulphate  "  solution,  for 
titration,  as  directed  on  p.  142,  portions  of  10  c.c.  are  titrated  in 
comparison  with  "  standard  quinine,"  for  percentage  of  cincho- 
riidine,  etc.  The  results  will  count,  on  the  basis  of  the  5  c.c.  or 
of  the  10  c.c.  of  filtrate  used,  in  per  cent,  of  the  salt  of  quinine 
taken.  That  is,  each  0.32  c.c.  of  ammonia  of  sp.  gr.  0.920  used  for 
10  c.c.  of  filtrate  (beyond  that  used  for  the  "standard  quinine'') 
indicates  0  001  gram,  or  0.1  per  cent.,  of  cinchonidine  hydrochlo- 
ride  in  the  commercial  quinine  hydrochloride  taken,  or  of  cin- 
chonidine hydrobromide  in  commercial  quinine  hydrobromide 
taken,  etc. 

Under  Hydrochlorate  of  Quinine  the  Br.  Ph.,  1885,  states 
that  "  it  may  be  converted  into  sulphate  of  quinine  by  dissolving 
it,  together  with  an  equal  weight  of  sulphate  of  sodium,  in  ten 
times  its  weight  of  hot  distilled  water,  and  setting  the  mixture 
aside  at  60°  F.  (15.5°  C.)  for  half  an  hour.  Such  sulphate  should 
respond  to  the  characters  and  tests,"  etc.,  no  further  directions 
being  given.  The  Ph  Fran.,  1884,  does  not  apply  tests  for  cin- 
chonidine to  hydrochloride  or  hydrobromide  of  quinine.  The 
Ph.  Germ.,  1882,  directs  to  evaporate  2  grams  of  hydrochloride 
of  quinine  with  1  gram  of  sodium  sulphate  and  20  grams  of 
water,  to  dryness,  digest  the  residue  with  12  grams  of  alcohol, 
evaporate  the  filtrate,  and  subject  the  resulting  quinine  sul- 
phate to  the  test  prescribed  for  this  salt.  The  U.  S.  Ph.,  1880, 
directs  for  quinine  hydrochloride  and  hydrobromide  alike  that 
"  1.5  gram  be  dissolved  in  15  c.c.  of  hot  distilled  water,  the  solu- 
tion stirred  with  0.75  gram  [for  the  hydrobromide,  0.60  gram] 
of  crystallized  sulphate  of  sodium  in  powder,  the  mixture  main- 
tained at  15°  C.  for  half  an  hour,  and  then  drained  through  a 
filter  only  large  enough  to  contain  it,  until  5  c.c.  of  filtrate  are 


148  CINCHONA   ALKALOIDS. 

obtained  ;  upon  treating  this  liquid  as  directed  for  the  corre- 
sponding test  under  quinine  (p.  144)  the  results  there  given 
should  be  obtained." — F.  B.  POWER*  states  that,  following  the 
U.  S.  Ph.  directions,  he  obtained  only  from  2  c.c.  of  filtrate  with 
the  hydrobromide,  and  only  about  1  c.c.  of  filtrate  in  testing  the 
hydrochloride ;  and  he  proposes  taking  30  c.c.  of  water  instead  of 
15  c.c.  for  the  1.5  'grams  of  hydrobromide  or  hydrochloride  of 
quinine.  C.  N.  LAKE"  has  avoided  the  difficulty  in  another 
way,  adopted  in  a  habitual  use  of  the  test  upon  these  salts, 
namely  :  by  repeatedly  adding  water  and  evaporating  to  dry  ness, 
with  stirring,  whereby  the  bulkiness  of  the  precipitated  mass  be- 
comes reduced,  and  the  5  c.c.  of  filtrate  are  obtained.  The  ob- 
vious remedy  for  deficiency  of  the  filtrate  (as  remarked  also  by 
Mr.  Lake)  is  to  take  larger  quantities  of  the  materials  without 
altering  their  proportion  to  the  water  (see  p.  139).  Certainly 
the  stated  proportion  of  water  is  an  influential  factor  in  the  test, 
not  to  be  varied  unless  a  correction  be  needful  to  preserve  the 
conventional  ratio3  of  1  to  10  between  the  sulphate  and  the 
water.  Such  a  correction,  as  seen  on  p.  147,  would  make  a 
slight  but  appreciable  diiference  with  the  hydrochloride,  not  an 
appreciable  difference  with  the  hydrobromide.  Greater  diffe- 
rences are  probably  due  to  the  presence  of  sodium  sulphate,  and 
bromide  or  chloride,  in  the  U.  S.  Ph.  application  of  the  test.  At 
all  events,  the  taking  of  twofold  or  threefold  the  quantities  of 
the  salts  and  the  water  directed  by  the  U.  S.  Ph.,  in  its  specified 
proportions,  does  not  constitute  a  departure  from  its  authority 
for  these  tests. 

In  the  ammonia  test  for  purity  of  Quinine,  free  alkaloid, 
a  weighed  quantity,  from  2  to  5  grams,  either  of  the  hydrate  or 
of  the  anhydrous  alkaloid  obtained  by  drying  to  a  constant  weight 
at  100°— 115°  C.,  may  be  converted  to  normal  sulphate  by  digest- 
ing with  warm  diluted  sulphuric  acid,  as  directed  for  the  pre- 

'1885:  "Contributions  Dept.  Phar.  Univ.  Wis.,"  p.  11. 

2 1885:  "The  Ph.  Application  of  Kerner's  Test  to  Quinine  and  its  Salts  ": 
Drug.  Cir,  29,  199  (Oct.) 

3  It  is  the  concentration  of  the  solution  of  alkaloids  not  quinine  that  is  to  be 
guarded  against  variation  in  the  test — a  test  for  the  quantity  of  these  alkaloids 
by  measure  of  the  concentration  of  the  ammonia  needful  to  dissolve  them. 
The  quinine  sulphate  concentration  is  securely  constant,  in  solution  sure  to  be 
saturated.  The  concentration  of  the  solution  of  "other  alkaloids"  is  not  un- 
derstood to  be  affected  by  the  absorption  of  a  good  part  of  this  solution  by  a 
bibulous  mass  of  imperfectly  crystallized  salt.  If  the  proportion  of  water  were 
materially  varied  by  entering  into  combination  as  crystallization-water,  this 
variation  would  be  a  proper  subject  of  correction.  But  in  the  two  cases  in 
hand  more  crystallization- water  is  liberated  than  is  taken  up,  the  difference 
being  immaterial. 


QUININE.  149 

cipitated  alkaloid  on  p.  146,  making  up  to  the  conventional 
volume  of  the  strictly  neutral  mixture  and  treating  further,  as 
there  directed.  Grams  of  quinine  hydrate  taken  X  11.5  (or  grams 
of  anhydrous  quinine  X  13.4)  =  c.c.  of  conventional  volume. 
Each  0.32  c.c.  of  ammonia-water  of  sp.gr.  0.920  used  intitration 
of  10  c.c.  of  filtrate  indicates  0.001  gram,  or  0.1  per  cent.,  of 
free  cinchonidine  in  the  commercial  free  quinine  tested,  etc. 
For  5  c.c.  of  filtrate  not  over  7  c.c.  of  ammonia-water  of  sp.  gr. 
0.960  should  be  required,  to  correspond  to  the  pharmacopoeial 
standard  for  quinine  sulphate. 

The  IT.  S.  Ph.  test  for  Quinine  (hydrate)  converts  the  alka- 
loid into  the  sulphate  by  drying  on  the  water- bath  a  wetted 
mixture  of  the  quinine  with  half  its  weight  of  ammonium 
sulphate.1 

In  the  ammonia  test  for  purity  of  Quinine  Bisulpliate,  it 
may  be  converted  to  the  normal  sulphate,  without  loading  the  so- 
lution with  alkali  sulphates,  as  follows :  A  weighed  quantity, 
from  2  to  5  grams,  of  the  bisulphate  is  dissolved,  in  a  graduated 
test-glass,  in  about  12  times  its  weight  of  warm  distilled  water. 
The  solution  is  carefully  divided  into  two  exactly  equal  portions 
by  volume;  from  the  one  portion  (taken  in  a  small  beaker)  the 
alkaloid  is  fully  precipitated  by  sodium  hydrate  solution,  and  the 
precipitate  washed  on  a  filter  until  the  washings  are  made  but 
slightly  cloudy  by  barium  chloride  solution,  when  the  drained 
precipitate  is  partly  dried  by  blotting-paper  and  transferred  from 
the  filter  to  the  other  portion  of  the  bisulphate  solution,  in  the 
graduated  test-glass  (p.  146).  The  mixture  is  now  heated  (by 
immersing  the  test-glass  in  hot  water),  exactly  neutralized  to 
litmus-paper  by  adding  dilute  sulphuric  acid  or  ammonia,  and 
the  volume  made  up  to  a  number  of  c.c.  equal  to  8  times  the 
number  of  grams  of  the  bisulphate  first  taken,  when  the  mix- 
ture is  crystallized  at  15°  C.  and  further  treated  as  directed  on 
p.  144  or  142,  taking  5  c.c.  of  the  filtrate  for  the  limit-test,  or 
10  c.c.  for  titration  parallel  with  "  standard  quinine  solution  "  to 
estimate  cinchonidine.  For  5  c.c.  of  the  filtrate  not  over  7  c.c. 
of  ammonia- water  of  sp.  gr.  0.960  should  be  used,  to  correspond 


1  Prof.  Power  (where  cited  on  p.  148)  found  that  with  1  gram  quinine  taken 
only  3  c.c.  filtrate  could  be  obtained.  Mr.  Lake  (where  cited,  p.  148),  taking 
the  1  gram  quinine,  obtained  the  required  5  c.c.  of  filtrate,  in  his  practice  as  an 
analyst,  by  evaporating  to  dryness  and  adding  water,  which,  he  says,  it  was 
not  necessary  to  do  over  three  times.  To  take  2  to  5  grams  of  the  alkaloid,  with 
half  its  weight  of  ammonium  salt,  and  the  tenfold  number  of  c.c.  of  water,  in- 
volves no  departure  from  the  authority  of  the  pharmacopoeia  for  the  require- 
ment. 


ISO  CINCHONA   ALKALOIDS. 

with  the  pharmacopceial  standard  for  normal  quinine  sulphate. 
And  for  10  c.c.  of  the  h'ltrate  each  0.32  c.c.  of  ammonia-water  of 
sp.  gr.  0.920  used  (beyond  that  used  for  the  "  standard  quinine") 
indicates  0.1  per  cent,  of  cinchonidine  bisulphate  (cryst.,  2H2O, 
HESSE)  in  the  article  under  examination. 

The  U.  S.  Ph.  directs  that  the  dried  salt  be  neutralized  with 
ammonia,  made  up  to  10  fluid  parts  for  1  part  of  crystals  taken, 
then  held  at  15°  C.  and  further  treated  as  in  the  test  of  the  nor- 
mal sulphate.  The  same  simple  operation  (drying  the  salt  with 
the  ammonia)  is  directed  by  the  Ph.  Germ.  The  presence  of 
the  ammonium  sulphate  resulting  from  the  neutralizing  with 
ammonia  probably  adds  severity  to  the  test ;  while  the  dilution 
to  10  fluid  parts  for  1  part  of  bisulphate  amounts  to  12.5  fluid 
parts  for  1  part  of  normal  sulphate  formed,  and  certainly  dimin- 
ishes the  severity  of  the  test.  The  U.  S.  Ph.  makes  the  opera- 
tion upon  1  gram  of  the  salt,  and  the  Ph.  Germ,  upon  2  grams 
of  the  salt.  POWER  1  has  proposed  to  take  1  gram  of  the  salt 
with  20  c.c.  of  water,  because  10  c.c.  of  water  fail  to  yield  5  c.c. 
of  filtrate.  Where  the  operator  is  unable  to  depart  from  the 
pharmacopoeia,  he  should  preserve  the  proportions  of  1  to  10  for 
the  grams  of  crystallized  salt  to  the  c.c.  of  the  mixture  digested 
at  15°  C.  If  any  departure  be  made  in  this  proportion,  it  should 
be  the  adoption  of  the  ratio  of  1  to  8,  when  the  salt  is  neutralized 
with  ammonia  or  neutralized  with  its  own  alkaloid  obtained  from 
a  divided  portion  of  that  taken. 

The  ammonia  test  of  Effloresced  Salts  of  Quinine. — The  Sul- 
phate and  the  Bisulphate  are  frequently  effloresced  when  taken 
for  the  ammonia  test,  and  the  hydrate  is  apt  to  have  less  than 
3H2O.  The  severity  of  the  test  is  thereby  increased,  in  propor- 
tion to  the  resulting  increase  of  concentration  of  the  alkaloids 
not  quinine.  All  deviations  of  the  concentration  may  be  avoided 
by  drying  the  salts  to  a  constant  composition,  taking  the  anhy- 
drous or  the  effloresced  form  by  weight,  and  making  up  the 
volume  for  digestion  at  15°  C.  according  to  the  following  data. 
Then  5  c.c.  (or  10  c.c.)  of  the  filtrate  will  in  each  instance  have 
the  same  conventional  limit  of  concentration  for  the  sulphates  of 
all  the  cinchona  alkaloids  : 

1  Where  cited  on  p.  148.  The  recommendation  is  to  increase  the  propor- 
tion of  water,  when  it  is  already  25  percent,  too  large.  The  pharmacopoeia  does 
not  take  1  gram  of  the  dried  salt,  as  Prof.  Power's  equation  (p.  14,  loc.  cit.} 
represents,  but  "  1  gram  of  the  salt " — the  words  "  previously  dried  at  100°  C." 
qualifying  "agitated  with  8  c.c.  of  distilled  water,"  and  the  procedure  of  dry- 
ing being  parallel  to  that  more  explicitly  laid  down  for  quininae  sulphas.  LAKE 
(where  cited  on  p.  148)  has  used  the  1  gram  with  10  c.c.,  and  obtained  the  need- 
ful 5  c.c.  of  nitrate  by  evaporating  to  dryness,  stirring,  and  adding  water. 


QUININE. 


Taking  1  part  by  weight  or 
"»  "  grams. 

Weight 
constant,  C. 

Molecules 
water. 

Per  ct. 
crystal, 
water. 

Fluid  parts 
(tinges  "  n  "c.c.) 
of  mixture. 

Crystallized  quinine  sulphate. 

7 

14  45 

10  0 

Effloresced        "              "       

See  p.  126. 

2 

4.60 

11  2 

Anhydrous        "              " 

100°  —  115° 

11  7 

Crystallized  quinine  bisulphate 

7 

23  00 

8  O1 

Effloresced                         "          .... 
Anhydrous         "              "          .... 
Quinine  hydrate    .  . 

See  p.  127. 
100° 
See  p.  126 

1 
8 

4.09 
14  28 

10.0 
10.3 
11  5 

Anhydrous  quinine 

100°  —  120° 

13  4 

IS 

'erze- 
Kindt 


Hesse's  test  for  Quinine  Sulphate  (see  p  116)  differs  in  prin- 
ciple from  Kerner's  in  using  ether,  instead  of  excess  of  ammonia, 
as  a  solvent  of  the  quinine,  and  differs  from  Liebig's  test*  in 

1  If  the  bisulphate  be  neutralized  with  its  own  alkaloid  obtained  from  a 
divided  portion  of  the  salt  weighed  and  taken,  the  ratio  is  the  same. 

2  "Liebig's  Test." — The  author  is  unable  to  cite  published  directions  of 
Liebig  for  the  test  which  has  gone  under  his  name  for  fully  thirty  years.     The 
test,  in  a  simple  form,  with  far  too  large  proportions  of  ether  and  ammonia,  *~ 
very  clearly  given,  in  1833,  on  the  sole  authorship  of  KINDT,  as  follows  (Ber. 
Urn's  Jahresbericht,  12  (1833),  218;  from  Branded  Archiv,  36,  254):  "Kin 
hat  folgende  Methode  zur  Entdekkung  der  Gegenwart  von  Schwefelsaurem 
Cinchonin  im  Chininsalz  angegeben.    Man  zerreibt  1  Gran  vom  Salze,  schiittet 
es  in  em  Probirglas,  und  giesst  1  Drachme  Aether  darauf,  womit  man  es  um- 
schilttelt;  alsdann  mischt  man  1  Drachme  Ammoniak  zu  und  schiittelt  wolil 
um.     Wenn  sich  die  Fliissigkeiten  wieder  scheiden,  findet  man  die  Scheidungs- 
linie  rein,  wenn  das  salz  frei  von  Cinchonin  war,  aber  die  geringste  Menge  Cin- 
chonin  im   Salz  setzsich  deutlich  erkennbar  aus  der  Grenze  zwischen  beiden 
Fliissigkeiten  ab."      In  1842  CALVERT  (Jour,  de  Phar  ;  Ann.  Chem.  Phar., 
48,  242)  undertakes  to  separate  cinchonine  by  its  insolubility  in  calcium  chloride 
solution  and  in  lime  solution,  and  refers  to  the  use  of  ammonia,  but  not  to  the 
use  of  ether,  as  a  solvent  of  quinine.    In  1843  R.  HOWARD  (Phar.  Jour.  Trans., 
2,  645)  says  that  cinchonine  sulphate  is  not  at  all  excluded  from  commercial 
quinine  sulphate  •'  by  any  test  "  which  he  has  "  happened  to  see  recommended," 
and  he  gives  a  test  by  weight  of  crystals  from  a  saturated  sulphate  solution.     In 
1852  SOUBEIRAN  (Jour,  de  Phar.,  1852,  Jan.;  Am    Jour.  Phar.,  24,  166)  cites 
Liebig's  authority  for  the  ether  test,  saying  only  "Liebig  has  suggested"  the 
detection  of  cinchonine  by  treating  15  grains  of  the  salt,  with  2  ounces  ammonia 
solution,  and  2  ounces  of  ether,  and  so  on,  the  proportions  being  nearly  those 
given  by  Kindt  in  1833,  though  the  quantities  are  15  times  as  large.     From 
about  this  time  (1852)  the  test  is  commonly  menlimed  in  literature  as  Liebig's 
test;  but  in  1851  or  1852  ZIMMER  (Jahr.  Chem.,  1852,  745;  Chem.  Vazette,  1852, 
449)  gives  the  test,  with  the  modern  proportions  of  ether  and  of  ammonia,  with- 
out naming  Liebig's  authority.     Also  HENRI  (1847)  separates  cinchonine  by 
ether  in  a  complex  process,  which  is  criticised  by  GUIBOURT  in  1851-52,  neither 
of  these  authors  speaking  of  Liebig.    In  Gmelin's  Chemistry  (Cav.ed.  17,  279)  the 
method  is  entitled  "The  Quinine  Test  of  Liebig,"  but  among  the  references 
to  as  many  as  a  dozen   published  authorities  Liebig's  name  is  not  found.     In 
this  historical  inquiry  it  may  further  be  noted  that  when  LIEBIG  reported  the 
elementary  analyses  of  quinine  and  cinchonine,  in  1831  (Ann.  Phys.  them., 


152  CINCHONA   ALKALOIDS. 

removing  the  excess  of  the  quinine  as  a  sulphate  before  separat- 
ing by  .ether.  The  directions  of  Hesse  are  as  follows  : 1  A  "  qui- 
nometer  "  is  provided,  this  being  a  test-tube  10-11  mm.  (0.39  to 
0.43  inch)  wide,  and  120  mm.  (4.7  inches)  long.  The  tube  is 
marked  at  a  capacity  of  5  c.c.,  and  again  at  a  capacity  of  6  c.c. ; 
the  entire  capacity  of  the  tube,  which  is  fitted  with  a  cork,  being 
10  or  12  c.c.  Of  the  quinine  sulphate  to  be  tested,  0.5  gram  is 
well  shaken  in  a  test-tube  with  10  c.c.  of  hot  water  (50°  to  60°  C.), 
and  set  aside  to  cool  for  ten  minutes,  shaking  with  care  to  prevent 
the  expulsion  of  the  contents.  The  liquid  is  now  passed  through 
a  filter  of  about  60  mm.  (2.4  inches)  diameter  into  the  quinome- 
ter,  up  to  the  5  c.c.  mark  ;  1  c.c.  of  ether  (sp.  gr.  0.724  to  0.728)  is 
added  (up  to  the  6  c.c.  mark),  and  then  5  drops  of  ammonia- water 
(sp.  gr.  0.96),  when  the  tube  is  corked  and  slowly  shaken.  Gra- 
nular crystals  appearing  within  3  minutes  after  shaking  indicate 
as  much  as  3  per  cent,  of  cinchonidine ;  at  10  minutes  after  shak- 
ing, about  2  per  cent,  of  cinchonidine.  After  standing  2  hours 
the  appearance  under  a  lens  of  granular  crystals  indicates  cincho- 
nidine ;  radiating  needles,  cinchonine  or  quinidine ;  no  crystals, 
the  absence  of  over  1  per  cent,  of  cinchonidine,  or  0.5  per  cent, 
of  quinidine,  and  of  over  0.25  per  cent,  of  cinchonine.  Absence 
of  crystals  after  12  hours  shows  that  less  than  1  per  cent,  of  cin- 
chonidine is  present.  If  now  the  cork  be  loosened,  and  the 
ether  permitted  slowly  to  evaporate,  0.5  per  cent,  of  cinchonidine 
will  leave  a  distinct  crystalline  residue.  The  final  residue  con- 
tains amorphous  quinine. 

The  test  of  Sulphate  of  Quinine  for  Cinchonidine  by  the 
Br.  Ph.,  1885,  on  the  principle  of  Hesse's  test,  is  much  more 
elaborate  than  the  operation  above  detailed  :  "  Test  for  Cincho- 

Pogg.,  [3],  21,  25),  he  specifies  the  purification  of  quinine  by  dissolving  it,  not 
in  ether,  but  in  ammonia  (on  the  plan  of  Kerner's  test),  *as  follows:  "Der 
breiartige  weisse  Niederschlag,  welcher  durch  verdunstes  Armnoniak  aus  der 
schwefelsauren  Auflosung  erhalten  worden  war,  loste  sich  beim  Erhitzen  in  der 
etwas  freies  Ammoniak  enthaltenden  Fliissigkeit  vollkomrnen  auf,  und  gab  bei 
dem  abkiihlen  ganz  Ammoniak  freie,  sehr  feine,  glanzende,  seidenartige  Nadeln 
von  Chinm." 

Liebig's  test  was  directed  by  the  U.  S.  Ph.  of  1860  and  of  1870,  in  the  fol- 
lowing terms:  "When  10  grains  of  the  salt  [Sulphate  of  Quinine]  are  agitated 
in  a  test-tube  with  10  minims  of  officinal  water  of  ammonia  [0.960]  and  60 
grains  of  ether  [0.750],  and  allowed  to  rest,  the  liquid  separates  into  two  trans- 
parent and  colorless  layers,  without  any  white  or  crystalline  matter  at  the  sur- 
face of  contact."  It  was  generally  stated  that  as  much  as  10  per  cent,  of  quini- 
dine sulphate  would  escape  detection  by  this  test.  Undoubtedly  larger  percen- 
tages both  of  quinidine  and  cinchonidine  are  liable  to  fail  of  recognition  with 
the  test  as  commonly  applied. 

1  O.  HESSE,  1878':  Archiv  d.  Phar.,  [3].  13,  490;  Am.  Jour.  Phar.,  51, 135; 
New  Rem.,  8,  139;  Jour.  Chem.  Soc.,  36,  280;  Zeitsch.  anal.  Chem.,  19,  247. 


QUININE.  153 

nidine  and  Cinchonine. — Heat  100  grains  (6.48  grams)  of  the 
sulphate  of  quinine  in  five  or  six  ounces  (142-170  c.c.)  of  boiling 
water,  with  three  or  four  drops  of  diluted  sulphuric  acid.  Set 
the  solution  aside  until  cold.  Separate,  by  filtration,  the  purified 
sulphate  of  quinine  which  has  crystallized  out.  To  the  filtrate, 
which  should  nearly  fill  a  bottle  or  flask,  add  ether,  shaking  oc- 
casionally, until  a  distinct  layer  of  ether  remains  undissolved. 
Add  ammonia  in  very  slight  excess,  and  shake  thoroughly,  so 
that  the  quinine  at  first  precipitated  shall  be  redissolved.  Set 
aside  for  some  hours  or  during  a  night.  Remove  the  superna- 
tent  clear  ethereal  fluid,  which  should  occupy  the  neck  of  the 
vessel,  by  a  pipette.  "Wash  the  residual  aqueous  fluid  and  any 
separated  crystals  of  alkaloid  with  a  very  little  more  ether,  once 
or  twice.  Collect  the  separated  alkaloid  on  a  tared  filter,  wash 
it  with  a  little  ether,  dry  at  212°  F.,  and  weigh.  Four  parts  of 
such  alkaloid  correspond  to  five  parts  of  crystallized  sulphate  of 
cinchonidine  o,r  of  sulphate  of  cinchonme. 

"  Test  for  Quinidine. — Recrystallize  50  grains  (3. 240  grams) 
of  the  original  sulphate  of  quinine  as  described  in  the  previous 
paragraph.  To  the  filtrate  add  solution  of  iodide  of  potassium, 
and  a  little  spirit  of  wine  [alcohol]  to. prevent  the  precipitation  of 
amorphous  hydriodides.  Collect  any  separated  hydriodide  of  quin- 
idine,  wash  with  a  little  water,  dry  and  weigh.  The  weight  repre- 
sents about  an  equal  weight  of  crystallized  sulphate  of  quinidine. 

"  Test  for  Cupreine  [see  p.  92]. — Shake  the  recrystallized 
sulphate  of  quinine,  obtained  in  testing  the  original  sulphate  of 
quinine  for  cinchonidine  and  cinchonine,  with  one  fluid-ounce 
(28.4  c.c.)  of  ether  (sp.  gr.  0. 724-0. 728)  and  a  quarter  of  an 
ounce  (7.1  c.c.)  of  solution  of  ammonia  (of  10$  strength),  and  to 
this  ethereal  solution,  separated,  add  the  ethereal  fluid  and  wash- 
ings also  obtained  in  testing  the  original  sulphate  for  the  two 
alkaloids  just  mentioned.  Shake  this  ethereal  liquor  with  a  quar- 
ter of  a  fluid-ounce  (7.1  c.c.)  of  a  ten  per  cent,  solution  of  caustic 
soda,  adding  water  if  any  solid  matter  separates.  Remove  the 
ethereal  solution.  Wash  the  aqueous  solution  with  more  ether, 
and  remove  the  ethereal  washings.  Add  diluted  sulphuric  acid 
to  the  aqueous  fluid  heated  to  boiling,  until  the  soda  is  exactly 
neutralized.  When  cold  collect  any  sulphate  of  cnpreine  that 
has  crystallized  out,  on  a  tared  filter,  dry,  and  weigh. 

"  '  Sulphate  of  Quinine  '  should  not  contain  much  more  than 
five  per  cent,  of  sulphates  of  other  cinchona  alkaloids." 

Water  of  Crystallization  in  Sulphate  of  Quinine. — HESSE  1 

'1880:  Ber.  d.  chem.  Oes.,  13,  1517-1520,  and  elsewhere. 


154  CINCHONA    ALKALOIDS. 

has  continued  to  maintain  that  perfect  crystals  of  pure  quinine 
sulphate  have  8H2O  (16.18$  of  water).  KEENER'  affirms  that 
no  quinine  sulphate  is  manufactured  that  contains  over  14  to  an 
extreme  of  14. 6$  of  crystallization-water ;  above  this  any  con- 
tained water  is  free  moisture.  Also  that  it  is  not  possible  to  dry 
the  voluminous  quinine  sulphate  of  commerce  without  some 
degree  of  efflorescence.  The  Ph.  Germ.  (1882)  (without  for- 
mulae) limits  the  loss  by  drying  at  100°  C.  to  15$.  The  Ph. 
Fran.  (1884)  gives  YH2O  (=14.45$)  in  the  formula,  and  limits 
the  loss  at  100°  C.  to  14.45$.  The  Br.  Ph.  (1885)  gives  7jH2O 
in  the  formula,  and  limits  the  loss  at  100°  C.  to  this  molecular 
proportion,  14.3$.  The  U.  S.  Ph.  (1880)  gives  7H2O  in  the  for- 
mula, and  limits  the  loss  of  weight  at  100°  C.  to  16.18$.  Mr. 
H.  B.  PAKSONS  2  reported  the  loss  of  water  by  drying  three  hours 
in  a  (boiling)  water-oven,  for  1015  samples,  of  American,  Ger- 
man, and  Italian  makers,  each  sample  representing  100  ounces, 
and  taken  from  a  can  not  previously  opened.  T^he  average  of 
loss  of  water,  for  all  the  samples,  was  13.84$ ;  for  any  single 
manufacturer  the  lowest  average  was  12.61$,  and  the  highest 
average  was  14.36$.  The  samples  of  one  maker  all  approached 
closely  to  12  53$  (6H2O).  In  the  report  the  writer  recommends, 
as  others  have  done,  the  pharmacopoeial  adoption  of  effloresced 
quinine  sulphate,  the  two-molecule  salt,  as  a  definite  and  stable 
form  of  the  alkaloid. 

QUINIDINE.  The  Conchinine  of  Hesse  3  C20H24N2O2=324. 
In  crystals  with  2|H2O=i396.  Chinidine.—  KationarFormula, 
p.  98 ;  Proportion  in  Cinchona  Barks,  p.  97.  Separation  from 
the  Bark,  in  total  alkaloids,  p.  102.  Separation  from  Cinchona 

M880:  Archiv  d.  Phar.,  [3],  17,  453. 

2 1884:  Proc.  Am.  Ptiarm.,  32,  457. 

3  The  name  quinidine,  in  German  "chinidine,"  was  given  to  the  alkaloid 
now  universally  known  as  cinchonidine,  in  1833,  by  HENRY  and  DELONDRE. 
Quinidine  was  itself  discovered,  in  chinoidine,  in  1849,  by  VAN  HEIJNINGEN, 
who  then  named  it  ^-quinine;  again,  in  commercial  cinchonine,  in  18.il,  by 
HLASIWETZ,  who  named  itcinchotine.  In  1853  PASTEUR,  believing  that  he  iden- 
tified Henry  and  Delondre's  quinidine  among  cinchona  alkaloids,  and  discover- 
ing another  which  in  fact  was  Henry  and  Delondre's  quinidine,  he  fixed  to  this 
the  name  cinchonidine,  still  retained.  The  name  "quinidine"  having  thus 
been  differently  applied,  HESSE  (1874)  proposes  to  drop  it,  and  use  the  name 
"  conchinine"  for  the  isomer  of  quinine.  Some  of  the  German  writers  employ 
Hesse's  nomenclature,  but  English-writing  chemists  translate  the  "conchinine  " 
of  Hesse  into  the  English  equivalent  of  German  '•  chinidine,"  namely:  quini- 
dine. And  this  accords  with  the  recommendation  of  the  Quinological  Con- 
gress at  Amsterdam  in  1877  Further  see  KERNER'S  history  of  this  nomen- 
clature, 1880:  Archiv  d.  Phar.,  [3],  16  (reprints).  The  6-quinidine  of  Kerner 
in  1862  is  the  quinidine  of  the  present  time. 


QUINIDINE.  155 

Alkaloids,  index  at  p.  112.  Distinction  from  other  Cinchona 
Alkaloids,  index  at  p.  100.  Microscopic  identification,  p.  101. 
.Rotatory  Power,  p.  123. 

The  free  alkaloid  has  been  hardly  known  in  commerce,  and  its 
sulphate  is  less  used  than  that  of  cinchonidine  or  cinchonine. 
The  chinoidine  obtained  as  a  by-product  from  certain  barks  is 
rich  in  quinidine. 

The  crystalline  forms  and  heat  reactions  of  quinidine  and 
its  salts  are  given  under  a,  the  solubilities  of  the  same  under  c, 
below.  Quinidine  is  identified  by  its  fluorescence  in  the  sul- 
phate and  its  response  to  the  thalleioquin  test  (d),  together  with 
the  free  solubility  of  the  sulphate  in  chloroform  and  its  greater 
solubility  in  water.  Also  by  precipitation  as  hydriodide  (d).  It 
is  separated,  by  solution  of  the  sulphate  in  chloroform,  or  pre- 
cipitation with  iodide,  or  otherwise  (0);  estimated,  usually  by 
weight  of  the  hydriodide  (/).  Tests  for  impurities  in  quini- 
dine sulphate  are  presented  under  g,  p.  157. 

a. — Quinidine  crystallizes  from  alcohol,  with  2JH2O,  in  large, 
lustrous,  monoclinic  prisms  or  needles,  efflorescent  in  the  air. 
From  ether  permanent  rhombohedrons  with  2H2O  are  obtained ; 
from  boiling  water  permanent  plates  with  1^H2O  (HESSE).  The 
whole  of  the  water  is  removed  at  or  below  120°  C.,  and  the  dry  al- 
kaloid melts  at  168°  C.  It  begins  to  brown  very  slightly  at  160° 
C.  (BLYTH).— Quinidine  sulphate,  (C2pHo4N2O2)2H2S64.2H2O, 
crystallizes  in  white,  silky  needles  or  in  long,  hard  prisms,  per- 
manent in  the  air,  giving  up  the  water  at  120*  C. — The  hisulphate 
crystallizes  in  asbestos-like  prisms,  with  4H2O. — Quinidine  hy- 
drochloride  crystallizes  in  asbestos-like  fibres,  with  H2O. — Qui- 
nidine oxalate,  normal,  crystallizes  with  H2O,  in  pearly  plates  or 
in  prisms. 

b. — In  taste  and  physiological  effects  quinidine  resembles 
quinine. 

c. — Quinidine  is  soluble  in  2000  parts  of  water  at  15°  C.,  in 
750  parts  of  boiling  water ;  in  26  parts  alcohol  of  80$  at  20°  C. ; 
in  22  parts  of  ether  of  sp.  gr.  0  729  at  20°  C.,  or  in  35  parts  of 
the  same  at  10°  C.  (HESSE,  1868).  In  809  parts  ether  of  0.72 
sp.  gr.  at  19°  C.  (VAN  DEB  BURG)  ;  in  76.4  parts  of  ether  at  10°  C. 
(DRAGENDORFF).  In  chloroform  or  amyl  alcohol  it  is  readily  solu- 
ble; in  petroleum  ether  difficultly  soluble.  Quinidine  neutral- 
izes acids  in  forming  normal  salts. 

Quinidine  sulphate  of  a  neutral  reaction  is  soluble  "  in  100 
parts  of  water  and  in  8  parts  of  alcohol  at  15°  C. ;  in  7  parts  of 


156  CINCHONA   ALKALOIDS. 

boiling  water,  and  very  soluble  in  boiling  alcohol ;  also  in  acidu- 
lated water  and  in  20  parts  of  chloroform,  but  almost  insoluble 
in  ether  "  (U.  S.  Ph.)  In  19.5  parts  chloroform  at  15°  C.,  in  9 
parts  at  62°  C.  (HESSE,  1 879). — Quinidine  hydrochloride  is  solu- 
ble in  62.5  parts  of  water  at  10°  C.,-and  freely  soluble  in  hot 
water,  in  alcohol,  and  in  chloroform ;  nearly  insoluble  in  ether. 
— Quinidine  hydrobromide,  anhydrous  (!)E  VRIJ,  1875),  is 
soluble  in  200  parts  of  water  at  14°  C. — Quinidine  oxalate, 
(Co0H2oN"oOp)oH2CoO4.HoO,  dissolves  in  150  parts  of  water  at 
15°  C. 

d. — In  solutions  of  the  sulphates,  and  especially  in  solutions 
acidulated  with  sulphuric  acid,  quinidine  exhibits  strong  blue 
fluorescence.  (See  Quinine,  d.)  The  chloroformic  solution  of 
the  sulphate  has  a  green  fluorescence  (HESSE,  1879). — Quinidine 
responds  to  the  thalleioquin  test  (p.  130).  Sulphuric  acid  gives 
no  color ;  Froehde's  reagent,  a  greenish  color. — Iodide  of  po- 
tassium causes  in  neutral  solutions  of  quinidine  salts  a  crystal- 
line precipitate  of  quinidine  hydriodide,  C20H24N2O2HI,  soluble 
in  1250  parts  of  water  at  15°  C.  (DE  VRIJ).  Immediate  precipi- 
tation is  obtained  only  in  somewhat  concentrated  solution,  and  is 
incomplete.  Full  crystallization  within  the  limit  of  solubility  is 
obtained  by  warming  the  mixture  and  stirring  it  with  a  glass  rod 
from  time  to  time  as  it  cools,  then  leaving  some  hours  at  a  low 
temperature,  stirring  at  intervals.  The  reagent  should  be  neutral, 
and  added  in  such  proportion  that  the  quantity  of  solid  potassium 
iodide  shall  nearly  equal  the  quantity  of  alkaloid  in  solution. 
The  crystals  slowly  formed  in  dilute  solutions  are  leaf -form.  In 
acidulous  mixtures  of  sufficient  concentration  bihydriodide  of 
quinidine  is  formed,  in  golden  crystals,  soluble  in  90  parts  of 
water  at  15°  C.  (DE  YEIJ). — With  the  alkalies  and  alkali  carbo- 
nates quinidine  gives  nearly  the  same  reactions  as  quinine,  the 
precipitate  being  very  much  less  soluble  in  excess  of  ammonia. 
In  presence  of  quinine  the  quinidine  precipitate  requires  a  good 
excess  of  ammonia  to  dissolve  it,  and  the  precipitate  is  apt  to  re- 
appear, crystalline  on  standing. — With  the  general  reagents  for 
alkaloids  quinidine  reacts  nearly  the  same  as  quinine,  so  far  as 
the  reactions  have  been  examined. — The  dextrorotatory  power  of 
quinidine  is  given  on  p.  123. 

e. — Separations  of  quinidine  are  obtained  chiefly  (1)  by  its 
crystallization  as  hydriodide  (d,  /*),  and  (2),  except  from  cincho- 
nine,  by  solution  of  the  sulphate  in  chloroform  (<?).  See  Separation 
of  Cinchona  Alkaloids,  p.  112,  for  an  index  of  methods  of  separa- 
tion. Also  compare  the  special  separations  of  Quinine  (f),  p.  141. 


CINCHONIDINE.  1 57 

. — Quantitative. — In  estimating  quinidine  as  hydriodide,  crys- 
tallization is  secured,  as  indicated  under  d,  giving  twenty-four 
hours  for  the  crystals  to  form.  The  drained  crystals,  sparingly 
washed,  are  dried  in  a  warm  place,  and  weighed  as  C20H24N2O2H  I, 
adding  y^-g-  of  the  weight  of  the  crystallizing  liquid  and  wash- 
ings. The  anhydrous  quinidine  constitutes  71.75  per  cent,  of  the 
total  hydriodide. 

g. — Tests  for  impurities. — "The  salt  [sulphate]  should  not 
be  more  than  very  slightly  colored  by  undiluted  sulphuric  acid 
(absence  of  [more  than  very  slight  proportions  of]  foreign  organic 
matters).  .  .  .  If  0.5  gram  each  of  sulphate  of  quinidine  and  of 
iodide  of  potassium  (not  alkaline  to  test-paper)  be  agitated  with 
10  c.c.  of  water  at  about  60°  C.  (140°  F.),  the  mixture  then  mace- 
rated at  15°  C.  (59°  F.)  for  half  an  hour,  with  frequent  stirring, 
and  filtered,  the  addition  to  the  filtrate  of  a  drop  or  two  of  water 
of  ammonia  should  not  cause  more  than  a  slight  turbidity  (absence 
of  more  than  small  proportions  of  conchonine,  cinchonidine,  or  qui- 
nine)" (U.  S.  Ph.,  1880).  One  part  quinidine  sulphate  dissolved 
in  10  parts  hot  water  is  digested  at  60°  C.  with  1  part  potassium 
iodide,  the  mixture  cooled,  with  agitation,  and  the  nitrate  tested 
with  1  or  2  drops  of  ammonia- water  (Ph.  Fran.,  1884). 

CINCHONIDINE. — The  Quinidine  of  HENKY  and  DELONDEE 
(1833).1  Isomeric  with  cinchonine,  C19H22N2O=294.a  Crystal- 
lizes anhydrous. — The  free  alkaloid  is  little  known  in  commerce, 
but  the  sulphate  since  about  1876  has  been  used  quite  largely, 
and  to  a  much  greater  extent  than  any  other  distinct  cinchona 
alkaloid  except  quinine.  Cinchonidine  is  the  chief  general  impu- 
rity in  quinine  salts  in  use. 

The  Kational  Formula  is  indicated  at  p.  98.  Proportion  in 
Cinchona  Bark,  p.  97.  Separation  from  the  Bark,  in  total  alka- 
loids, pp.  102-111.  Separation  from  other  Cinchona  Alkaloids, 
index  of  methods  at  p.  112.  Distinction  from  other  Cinchona 
Alkaloids,  index  of  methods  at  p.  100.  Microscopic  identifica- 
tion, p.  101.  Eotatory  Power,  p.  123. 

The  crystalline  forms  and  heat-reactions  of  cinchonidine  and 
its  salts  are  given  under  #,  and  their  solubilities  under  c  (p.  158). 
Cinchonidine  is  characterized  by  chemical  reactions  stated  under 

'Also  of  WINCKLER,  1844.  See  foot-note  under  Quinidine  (p.  154).  This 
alkaloid,  isomerie  with  cinchonine  or  a  mixture  containing  it,  was  named  cin- 
clionidine  by  PASTEUR  in  1853,  and  by  WITTSTEIN  in  1856.  At  present  all  au- 
thorities agree  in  this  name. 

*  SKRAUP,  1878.  PASTEUR,  C2oH24NaO,  1853.  See  foot-note  under  Cincho- 
nine. 


158  CINCHONA  ALKALOIDS. 

d  (p.  159),  the  tartrate  precipitate  with  concurring  qualitative  re- 
actions being  the  chief  dependence  for  identification.  The  alka- 
loid is  estimated  by  weight  of  the  tartrate  or  of  the  free  alkaloid 
(f ).  The  tests  for  impurities  and  the  amount  of  water  of  crys- 
tallization of  the  sulphate  are  discussed  under  g,  p.  160. 

a. —  Crystallization  and  heat  reactions. — Cinchonidine  crystal- 
lizes,  anhydrous,  in  distinct,  lustrous  forms  ;  from  alcohol  in  short 
prisms ;  from  dilute  alcohol  in  fine,  thin  plates.  It  melts  at 
200°-201°  C.  (HESSE,  GLAUS,  1881).—  Cinchonidine  sulphate  crys- 
tallizes in  white,  silky,  lustrous  needles  or  in  thin,  quadratic  prisms. 
"  In  colorless  silky  crystals,  usually  acicular "  (Br.  Ph.,  1885). 
"  Ordinarily  from  aqueous  solution  little  concentrated,  in  bril- 
liant needles,  with  6H2O.  From  concentrated  [hot]  aqueous  so- 
lution, in  [hard]  prisms,  with  3H2O.  And  from  alcohol  in  fine 
prisms,  with  2H2O.  The  salt  with  61I2O  is  officinal"  (Ph.  Fran., 
1884).  The  crystals  containing  6H2O  effloresce  to  some  extent  in 
the  air,  losing  either  one  or  four  of  the  6H2O,  as  determined  by 
the  mode  of  production  of  the  crystals  (Ladenburg's  "  Handwor- 
terbuch").  In  moist  air  the  anhydrous  salt  gains  2H2O.  All 
water  of  crystallization  is  expelled  on  the  water-bath.  Cinchoni- 
dine sulphate  with  quinine  sulphate  crystallizes  with  6H2O  (Kop- 
PESCHAAR,  1885). —  Cinchonidine  hydrochloride,  with  1  molecule 
of  H2O,  forms  characteristic  crystals,  double  pyramids,  octahe- 
drons" (HESSE).  From  supersaturated  solution  silky,  prismatic 
needles  are  sometimes  obtained,  with  2H2O.  A  bihydrochloride 
is  also  obtained,  forming  large,  lustrous,  monoclinic  crystals  with 
1  molecule  of  water. —  Cinchonidine  hydrobromide  crystallizes, 
with  H2O,  in  long,  colorless  needles  (Ph.  Fran.)  The  dihydro- 
bromide,  with  2H2O,  crystallizes  in  very  slightly  yellowish  pro- 
longed prisms  (PhT  Fran.) — Cinchonidine  tartrate,  normal,  with 
2H2O.  is  a  white  crystalline  precipitate,  becoming  anhydrous  at 
100°  C. —  Cinchonidine  oxalate,  normal,  crystallizes,  with  2  or 
6  H2O,  in  prisms  or  a  crystalline  powder. 

#. — Cinchonidine  has  a  very  bitter  taste,  and  is  administered 
in  doses  not  far  from  those  of  quinine.  In  excess  it  is  liable  to 
prove  poisonous,  with  action  resembling  that  of  picrotoxine  (SEE 
and  BOCHEFONTAINE,  1885).  Death  has  resulted  from  taking  160 
grains  (WILLIAMS,  1884). 

c. — Solubilities. — Cinchonidine  is  soluble  in  1680  parts  of 
water  at  10°  C.,  in  20  parts  of  80$  alcohol,  in  76  parts  of  ether 
of  sp.  gr.  0.729,  and  easily  soluble  in  chloroform  (HESSE,  -1865). 
In  16.3  parts  of  alcohol  of  97$  at  13°  C.,  and  in  188  parts  ether 


CINCHONIDINE.  159 

of  sp.  gr.  0  72  at  15°  C.  (HESSE,  1880).  Readily  soluble  inamyl 
alcohol.  Slightly  soluble  in  ammonia.  In  presence  of  quinine 
its  solubility  in  ether  is  increased.  The  normal  salts  of  cinchoni- 
dine,  with  ordinary  acids,  are  neutral. 

Cinchonidine  sulphate,  (C19H22N2O)2H2SO4 .  6H2O = 794  (see 
a\  is  soluble  "in  100  parts  of  water  and  in  71  parts  of  alcohol  at 
15°  C.  (59°  F.),  in  4  parts  of  boiling  water,  in  12  parts  of  boiling 
alcohol,  freely  in  acidulated  water,  and  in  1000  parts  of  chloro- 
form (the  undissolved  portions  becoming  gelatinous) ;  very  spar- 
ingly soluble  in  ether  or  benzene  "  (U .  S.  Ph.)  In  300  parts 
boiling  chloroform.  Mixed  with  quinine  sulphate  it  becomes 
somewhat  soluble  in  ether  (PAUL,  1877).  In  presence  of  cincho- 
nine  or  quinidine  sulphate  its  solubility  in  chloroform  is  increased 
(Prescott  and  Thuin,  1878).  —  Cinchonidine  hydrochloride, 
C19H22ISr2O  HC1.H2O:=  348.4  (see  a),  is  soluble  in  30  parts  of 
water  at  15°  C.,  freely  soluble  in  boiling  water,  in  alcohol,  and  in. 
chloroform,  and  soluble  in  325  parts  of  ether  at  10°  C.  (CABLES, 
1874).  From  the  chloroformic  solution,  in  long  standing, 
there  are  formed  prismatic  crystals  of  an  in  stable  compound 
with  chloroform  (HESSE,  1875). — Cinchonidine  hydrobromide, 
C19H22]Sr2OHBr.H2O=393  (Br=80),  is  soluble  in  40  parts  of 
cold  water,  and  freely  soluble  in  hot  water  (Ph.  Fran.) — Cincho- 
nidine tartrate,  (C19H22N2O)2C4H6O6 .  2H2O,  is  soluble  in  1265 
parts  of  water  at  10  C.,  less  soluble  in  solution  of  rochelle  salt. — 
The  normal  oxalate,  (C19H22N2O)2H2C2O4. 6H2O,is  soluble  in  252 
parts  of  water  at  12°  C.  for  1  part  of  the  anhydrous  salt. 

d. — Cinchonidine  does  not  form  fluorescent  solutions  nor 
give  the  thalleioquin  reaction. — Potassium  sodium  tartrate  and 
other  normal  tartrates  precipitate  cinchonidine,  as  normal  tar- 
trate (see  above,  c\  crystallizing  from  hot  solution  in  fine  nee- 
dles. An  excess  of  the  reagent  renders  the  test  the  more  delicate. 
A  separation  from  cinchonine,  and  to  some  extent  from  quini- 
dine, hardly  at  all  from  quinine. — Cinchonidine  is  precipitated 
from  solutions  of  its  salts  by  the  alkalies  and  alkali  carbonates, 
the  precipitate  appearing  at  first  amorphous,  slowly  becoming 
crystalline,  and  being  somewhat  soluble  in  excess  of  ammonia 
(see  Quinine,  g,  "  Kerner's  Test ").  The  general  reagents  for 
alkaloids  give  customary  reactions  with  cinchonidine. — In  the 
test  for  iodosulphate  (see  Quinine,  d,  Herapathite,  p.  131)  green 
crystals  of  golden  lustre  are  obtained. — Respecting  the  microche- 
mical  test  with  sulphocyanate,  see  under  Cinchona  Alkaloids, 
p.  101;  the  levorotatory  power,  p.  122. 

e. — Separations  of  cinchonidine  are  indexed  under  Cinchona 


160  CINCHONA  ALKALOIDS. 

Alkaloids,   Separation  of,  p.  112.      Compare  also  with  special 
methods  for  the  separation  of  Quinine,  p.  139. 

f. — Cinchonidine  can  be  estimated,  gravimetrically,  as  anhy- 
drous alkaloid  by  drying  the  precipitate  obtained  with  sodium 
hydrate  on  the  water-bath  (a).  More  often  it  is  estimated  (ac- 
cording to  directions  given  under  Cinchona  Alkaloids,  Separa- 
tion) by  weight  of  the  anhydrous  tartrate  (C19H22N2O)2C4116O6 
=  738  (79.67$  cinchonidine).  The  precipitate  is  dried  on  the 
water-bath. — As  to  optical  estimation,  see  p.  124  under  Cin- 
chona Alkaloids. — For  estimation  in  mixture  with  quinine,  both 
as  sulphates,  by  action  of  ammonia,  see  under  Quinine,  <?, 
«  Kerner's  Test." 

g. —  Tests  for  impurities—  "  If  0.5  gram  of  the  salt  [sul- 
phate] be  digested  with  20  c.c.  of  cold  distilled  water,  0.5  gram 
of  tartrate  of  potassium  and  sodium  added,  the  mixture  mace- 
rated, with  frequent  agitation,  for  one  hour  at  15°  C.  (59°  F.), 
then  filtered  and  a  drop  of  water  of  ammonia  added  to  the  fil- 
trate, not  more  than  a  slight  turbidity  should  appear  (absence  of 
more  than  0.5  per  cent,  of  sulphate  of  cinchonine,  or  of  more 
than  1.5  per  cent,  of  sulphate  of  quinidine) "  (IT.  S.  Ph.,  1880).1 
The  test  originated  with  HESSE  (1875),  who  directed  to  digest 
0.5  gram  of  the  salt  with  20  c.c.  water  at  about  60°  C.,  add  1.5 
grams  of  the  tartrate,  and  after  an  hour  filter  and  test  with  am- 
monia. The  Ph.  Fran.  (1884)  directs  digestion  with  boiling 
water,  40  parts,  and  an  excess  of  the  tartrate,  then  setting  aside 
24  hours  before  testing.  The  three  parts  of  tartrate  directed  by 
Hesse  give  a  little  closer  results  than  are  obtained  with  addition 
of  one  part  (c,  p.  159).  The  test  does  not  reveal  quinine,  tartrate 
of  which  takes  910  parts  water  at  10°  C.  to  dissolve  it,  but  shows 
either  cinchonine  or  quinidine.  To  test  for  presence  of  quini- 
dine, add  to  the  filtrate  from  tartrate  precipitation  potassium 
iodide  equal  to  quantity  of  cinchonidine  salt  taken,  and  stir  from 
time  to  time,  when  •  quinidine  will  be  revealed  by  precipitation, 
and  the  second  filtrate  can  be  tested,  with  a  drop  of  ammonia- 
water,  for  cinchonine.  Either  quinine  or  quinidine  will  be  re- 
vealed by  fluorescence  (Quinine,  d). — The  sulphate  u  should  not 
be  colored  by  addition  of  sulphuric  acid  (absence  of  foreign  or- 
ganic matters)  "  (U.  S.  Ph.,  1880) ;  should  not  suffer  "  more  than 
a  faint  yellow  coloration"  (Br.  Ph.,  1885). 

As  to  amount  of  crystallisation-water  in  cinchonidine  sul- 
phate, see  a.  The  loss  by  drying  at  100°  C.  is  limited  by  the 

1  TEETER,  Univ.  Mich.,  1880:  New  Rem.,  9,  258. 


CINCHONINE.  161 

U.  S.  Ph.  and  Br.  Ph.  to  the  amount  of  3H2O,  or  7.3  per  cent.; 
by  the  Ph.  Fran,  to  the  proportion  of  6H2O,  13.60  per  cent. 
Five  ordinary  commercial  samples,  dried  at  100°  C.  and  cooled  in 
a  desiccator,  gave  a  loss  of  from  6.36  per  cent,  to  7.04  per  cent.1 

CINCHONINE.  C-^IL^^O  —  294.a  Crystallizes  anhydrous. — 
See  Cinchona  Alkaloids,  p.  97,  for  yield  in  cinchona  barks,  and 
p.  98  for  chemical  constitution. 

Methods  of  Separation  from  the  Bark,  in  the  total  alkaloids, 
are  given  pp.  102  to  111.  From  the  other  cinchona  alkaloids 
the  methods  of  separation  are  indexed  at  p.  113,  the  means  of 
distinction  are  indexed  at  p.  100.  Methods  of  microscopic  in- 
uiry,  p.  101.  Rotatory  Power,  p.  123.  Crystallization  and 
^eat-Reactions  for  the  alkaloid  and  its  salts,  below.  Solubili- 
ties of  the  alkaloid  and  its  salts,  p.  162.  Physiological  effects, 
p.  162. 

Cinchonine  is  identified  by  the  agreement  of  a  number  of  al- 
kaloidal  reactions  and  solubilities,  and,  after  separation,  by  nega- 
tive results  excluding  other  alkaloids  {d) ;  the  reaction  with  fer- 
rocyanide,  carefully  obtained  under  the  magnifier,  is  somewhat 
characteristic,  as  likewise  is  the  iodine  reaction.  For  separations, 
references  are  noted,  in  addition  to  those  above,  at  e,  p.  164. 
The  alkaloid  is  estimated  by  its  weight  in  the  free  state,  anhy- 
drous (/"),  and  has  been  estimated  by  Mayer's  solution  (p.  164). 
Tests  for  purity  are  given  (g)  at  p.  164. 

a. — Crystallization  and  Heat- Reactions. — Cinchonine  ap- 
pears in  white  prisms  or  needles,  anhydrous,  in  the  monoclinic 
system,  obtained  by  crystallization  from  alcohol.  In  watery  so- 
lution of  its  salts  ammonia  gives  a  flocculent,  crystalline  precipi- 
tate ;  in  solution  of  its  salts  in  dilute  alcohol  needles  are  obtained 
by  action  of  ammonia.  It  melts  at  268.8°  C.  (SKRAUP,  1878). 
Quickly  heated,  at  248°-252°  C. ;  slowly  heated,  at  236°  C.  (HESSE, 
1880).  Heated,  not  quite  to  the  melting  point,  in  a  stream  of 
hydrogen  or  ammonia,  a  sublimate  is  obtained,  of  undecomposed 
cinchonine,  in  prismatic  needles,  with  products  of  partial  decom- 

1  Taking  cinchonidine  at  Ci9H22  .  .  .,     6H20=13.60  per  cent,  of  the  sulphate. 
atC20H24...,     6H2O=:13.13 
at  C19H22  .  .  .,     3H2O=  7.30  "  " 

atC20H24  .  .  .,     3H20=  7.03  "  " 

'SKRAUP,  1878.  PASTEUR,  1853,  C20H24N2O.  Skraup  found  it  necessary  to 
separate  Cinchotine,  Ci9H24NaO  (p.  93),  to  obtain  pure  cinchonine  for  analysis. 
His  figures  support  the  new  formula  better  than  they  do  the  old.  Hesse  ac- 
cepts Skraup's  formula ;  and  it  is  taken  as  the  basis  of  hypotheses  of  the  consti- 
tution of  cinchona  alkaloids  (p.  98).  Pasteur's  formula  is  retained  in  the  Br. 
Ph.  of  1885;  Skraup's  is  adopted  in  the  Ph.  Fran,  of  1884 


1 62  CINCHONA  ALKALOIDS. 

position  (HLASIWETZ,  1851).  In  melting  it  turns  brown  and  sub- 
limes slowly. 

Ginchonine  sulphate,  with  2H2O,  crystallizes  in  short,  hard, 
monoclinic  prisms,  transparent,  of  a  vitreous  lustre,  permanent 
in  the  air,  parting  with  all  the  crystallization- water  at  100°  C. 
Triturated  at  100b  C.  it  glows  with  greenish  light.  It  melts  at 
about  240°  C. — Cinchonine  hydrochloride,  with  21I2O,  forms 
four-sided  rhombic  prisms  or  iine,  silky  needles,  permanent  in 
the  air,  efflorescent  in  a  desiccator,  becoming  anhydrous  at  100°  C., 
and  melting  at  about  130°  C. — The  hydrobromide  forms  long, 
lustrous  prismatic  needles  (LATOUR,  1870  ;  BULLOCK,  1875). — • 
The  hydriodide,  normal,  crystallizes,  with  H2O,  from  a  hot-satu- 
rated solution,  in  hard,  colorless,  monoclinic  prisms. — The  tar- 
trate,  normal,  with  2H2O,  crystallizes  from  a  hot  solution  in 
clusters  of  needles. — Cinchonine  oxalate,  normal,  with  2H2O, 
appears  in  crystalline  powder,  or  from  dilute  hoi  solution  in 
large  prisms,  becoming  anhydrous  at  130°  C. 

J. — Free  cinchonine  is  nearly  tasteless  at  first,  with  an  in- 
creasing bitter  after-taste.  The  soluble  salts  of  cinchonine  are 
very  bitter. — The  dose  of  the  sulphate  is  1  to  10  grains  (Br.  Ph.^) 

c. — /Solubilities. — "  Almost  insoluble  in  hot  or  cold  water, 
soluble  in  110  parts  of  alcohol  at  15°  C.  (59°  F.),  in  28  parts  of 
boiling  alcohol,  371  parts  of  ether,  350  parts  of  chloroform,  and 
readily  soluble  in  diluted  acids"  (U.  S.  Ph.)  In  3670  parts 
water  at  20°  C. ;  in  371  parts  of  ether  of  sp.  gr.  0.73  at  20°  C. ; 
in  125.7  parts  of  alcohol  of  sp.  gr.  0.852  at  20b  C.  (HESSE.  1862). 
In  356  parts  of  chloroform  strictly  alcohol-free,  at  17°  C.,  but 
more  freely  soluble  in  mixtures  of  chloroform  and  alcohol  than 
in  alcohol  alone  (OUDEMANS,  1873).  In  40  parts  of  "chloro- 
form" (PETTENKOFEK)  ;  in  35  parts  of  "chloroform"  (HAGER). 
Moderately  soluble  in  amyl  alcohol ;  sparingly  soluble  in  hot 
benzene  ;  scarcely  at  all  soluble  in  cold  benzene.1  Nearly  inso- 

1In  1875  the  writer  made  determinations  of  solubilities  of  cinchonine  in  su- 
persaturation  with  certain  water-washed  solvents,  with  the  results  which  follow. 
The  "  nascent"  state  was  that  of  liberation  from  sulphate  solution  by  ammonia, 
while  in  contact  with  the  hot  solvent,  all  the  solvents  being  applied  at  their 
boiling  points: 

Cinchonine.  Ether.  Chloroform.        Amyl  ale.  Benzene. 

At  15°  C. :  sp.  gr.  0.7290.    sp.  gr.  1.4953.    sp.  gr.  0.8316.    sp.  gr.  0.8766. 

Crystallized 719  828 

Amorphous 563  ...  40  531 

Nascent 526  178  22  376 

From  "Comparative  Determinations  of  the  Solubilities  of  Alkaloids  in  Crystal- 
line, Amorphous,  and  Nascent  Conditions:  Water-washed  Solvents  being  used." 
—A.  A.  A.  S.,  1875,  24,  i.  114;  Jour.  Chem.  Soc.,  29,  403;  Am.  Chem.,  6,  84. 


CINCHONINE.  163 

luble  in  petroleum  benzin  (DRAGENDORFF).  But  slightly  soluble 
in  ammonia- water. — Cinclionine  neutralizes  the  strong  mineral 
acids,  its  sulphate  having  "  a  neutral  or  faintly  alkaline  reaction  " 
(U.  S.  Ph.) 

Cinchonine  sulpJiate,  (C19H22N2O)2H2SO4 .  2H2O,  is  soluble 
"in  about  TO  parts  of  water  and  in  6 "parts  of  alcohol  at  15°  C. 
(59°  F.),  in  14  parts  of  boiling  water,  1.5  parts  of  boiling  alcohol, 
60  parts  of  chloroform,  and  easily  soluble  in  diluted  acids ;  in- 
soluble in  ether  or  benzene"  (IL  S.  Ph.)  In  65.5  parts  water 
at  13°  C.  (HESSE). 

Cinchonine  hydrochloride,  C19H22N2O  HC1.2II2O,  is  soluble 
in  24  parts  of  water  at  lu°  C. ;  in  1.3  parts  of  alcohol  of  sp.  gr. 
0.85  at  16°  C. ;  in  273  parts  of  ether  of  sp.  gr.  0.7305  at  15°  C. 
(HESSE). — The  hydrobromide  dissolves  in  18  parts  of  water  at 
21°  C.  (BULLOCK,  1875),  and  is  freely  soluble  in  alcohol.— The  hy- 
driodide,  C19H22NoO  HI.H2O,  is  freely  soluble  in  water,  in  al- 
cohol, and  in  chloroform,  and  somewhat  soluble  in  ether. — The 
normal  tartrate,  (C19H22N20)2C4H6O6.2H2O,  is  soluble  in  33 
parts  of  water  at  16°  C,  (HESSE),  the  solution  having  a  slightly 
alkaline  reaction. — The  tannate  is  very  slightly  soluble  in  water, 
and  is  not  soluble  in  all  proportions  of  cold  hydrochloric  acid.— 
Normal  oxalatt,  (C19H22N2O)2H2C2O4.2H2O,  dissolves  in  104 
parts  of  water  at  10°  C. 

d.— In  qualitative  reactions  cdnchonine  is  characterized  by 
negative  results.  It  does  not  respond  to  the  thalleioquin  test ; 
its  solutions  do  not  fluoresce ;  its  hydriodide  and  its  tartrate  are 
freely  soluble  in  water.  Its  periodides  and  iodosulphates  are 
distinguished  from  those  of  quinine  only  by  a  careful  observance 
of  conditions.  Potassium  ferrocyanide  solution  not  in  excess, 
witli  slightly  acidulated  solutions  of  cinchonine  salts,  gives  a 
yellowish-white  precipitate  of  cinchonine  ferrocyanide,  at  first 
amorphous,  becoming  crystalline  on  standing  or  while  cooling,  in 
radiate  or  fan-like  clusters  or  rhombic  plates,  as  seen  under  the 
microscope.  The  crystals  are  golden-yellow.  The  precipitate  is 
soluble  in  excess  of  the  reagent,  more  readily  before  crystallizing. 
The  solution  made  by  dissolving  the  amorphous  precipitate  in 
just  enough  excess  of  the  reagent  soon  yields  crystals  again  (a 
difference  from  the  reaction  with  quinine,  BARFOED).  Quinine 
gives  a  precipitate  more  permanently  soluble  in  excess  of  the  re- 
agent.— If  a  warm-saturated  alcoholic  solution  of  cinchonine 
be  neutralized  with  hydrochloric  or  very  slightly  acidified  with 
acetic  acid,  then  to  each  c.c.  about  10  drops  of  a  one  per  cent,  so- 
lution of  iodine  with  potassium  iodide  be  added,  and  water  added 


164  CINCHONA  ALKALOIDS. 

to  incipient  precipitation,  fine,  lustrous  red-brown  to  brown-yel- 
low crystals  of  superiodide  are  gradually  formed  in  the  cooling 
of  the  liquid.  The  forms  are  four-sided  rhombic  plates.  Under 
just  these  conditions,  and  in  absence  of  sulphates,  quinine  gives 
a  precipitate  of  tarry  consistence  (BARFOED,  1881).  Treated  as  a 
sulphate,  as  directed  under  Quinine,  d,  for  herapathite,  cincho- 
nine  gives  nearly  black  crystals,  brown  to  brown-yellow  when  in 
thin  layers  under  the  microscope. 

The  general  reagents  for  alkaloids  precipitate  cinchonine, 
in  most  cases  quite  perfectly.  Tannic  acid  gives  a  precipitate 
not  easily  dissolved  by  hydrochloric  acid.  The  alkali  hydrates 
and  carbonates  give  a  quite  complete  precipitate  of  cinciionine 
(see  #),  not  at  all  soluble  in  excess  of  sodium  hydrate,  and  (in 
absence  of  other  cinchona  alkaloids)  almost  insoluble  in  excess 
of  ammonia.  (See  under  Quinine,  <?,  "  Kerner's  Test ").  In 
dilute  solutions,  and  more  favorably  with  excess  of  ammonia,  the 
precipitate  becomes  crystalline  on  standing  a  short  time,  and  is 
seen  under  the  microscope  in  radiating  tufts  of  needles. 

e. — Separations  of  cinchonine  are  indexed  under  Cinchona 
Alkaloids,  Separation  of,  p.  113.  Compare  also  special  modes 
•of  separation  of  Quinine,  p.  139. 

f. — Quantitative. — Cinchonine  is  estimated,  gravimetrically, 
as  free  alkaloid,  anhydrous.  From  aqueous  solution  of  its  salts  it 
is  precipitated  by  solution  of  sodium  hydrate,  washed  with  water, 
and  dried  at  100°  C.  It  may  be  estimated  by  alkalimetry,  with 
tenth  or  hundredth  normal  sulphuric  acid  solution.  With  Mayer's 
solution  the  equivalent  of  1  c.c.  was  given  by  Mayer  (1862)  at 
0.0102  gram,  and  the  composition  of  the  precipitate  was  indi- 
cated to  be  C19H22N2O  HI  HgI2  by  Groves  (1859),  but  further 
data  are  needful  as  to  the  value  of  the  precipitation,  and  the 
action  of  the  reagent  is  greatly  affected  by  conditions. 

g. — Tests  for  distinctions  and  impurities. — "  A  solution  of 
the  alkaloid  in  dilute  sulphuric  acid  should  not  exhibit  more 
than  a  faint  blue  fluorescence  (absence  of  more  than  traces  of 
quinine  or  quinidine).  On  precipitating  the  alkaloid  from  this 
solution  by  water  of  ammonia  it  is  very  sparingly  dissolved  by 
the  latter  (difference  from  and  absence  of  quinine),  and  requires 
at  least  300  parts  of  ether  for  solution  (difference  from  quinine, 
quinidine,  and  cinchonidine)."  If  the  sulphate  "  be  macerated 
for  half  an  hour,  with  frequent  agitation,  with  TO  times  its  weight 
of  chloroform  at  15°  C.  (59°  K),  it  should  wholly,  or  almost 
wholly,  dissolve  (any  more  than  traces  of  sulphate  of  cinchoni- 


QU I  NO  LINE.  165 

dine  or  sulphate  of  quinine  remaining  undissolved).  It  should 
not  be  colored  by  contact  with  sulphuric  acid  (absence  of  foreign 
organic  matters)."  "If  1  gram  [of  the  sulphate]  be  dried  at  100° 
C.  until  it. ceases  to  lose  weight,  the  residue,  cooled  in  a  desicca- 
tor, should  weigh  not  less  than  0.952 '  gram  "  (U.  S.  Ph.,  1880). 
"Twenty-five  grains  of  the  salt  should  lose  1.26  grains  of  mois- 
ture when  dried  at  212°  F.  (100°  C.),  and  should  then  almost 
wholly  dissolve  in  four  ounces  by  weight  of  chloroform  "  (Br. 
Ph.,  1885). 

QumoLiNE. — Chinoline.  Leucoline.  C9H7N=129. — The 
structure  of  naphthalene  with  N  in  the  place  of  one  CH  (Korner, 
1870).  (See  under  Constitution  of  Cinchona  Alkaloids,  p.  97). 

An  artificial  volatile  alkaloid  obtained  as  follows :  (1)  By 
distilling  cinchonine  or  quinine,  strychnine  or  brucine,  with 
fixed  alkali.  In  presence  of  copper  oxide  the  quinoline  is  obtained 
nearly  free  from  lepidine  (C10H9N)  and  dispoline  (C^H^^T), 
next  homologous  members  of  the  quinoline  series  (CnH^^N). 
(2)  The  later  distillate  of  coal-tar,  the  "  dead- oil,"  contains  qui- 
noline. For  some  years  this  product  was  held  not  identical  but 
only  isomeric  with  the  quinoline  from  cinchonine,  and  it  was 
named  leucoline,  C9H7N.  In  1883  HOOGEWEEFF  and  v.  DOEP 
obtained  cinchonine-quinoline  free  from  previous  impurities, 
whereby  its  identity  with  the  quinoline  of  coal-tar  or  bone-oil 
is  believed  to  be  established.  The  same  investigators,  however, 
find  an  isomer  of  quinoline  in  bone-oil.  (3)  From  bone-oil.  (4) 
By  synthesis  in  several  ways,  best  from  nitrobenzene,  with  ani- 
line, according  to  the  equation  on  p.  97.  As  obtained  from 
these  several  sources  quinoline  is  itself  one  body. 

But  as  manufactured,  either  for  coloring  matters  or  for  me- 
dicinal purposes,  quinoline  is  likely  to  retain  some  degree  of 
impurities  derived  from  its  sources.  Cincho-quinoline  is  ac- 
companied by  lepidine.  Artificial  quinoline  is  sometimes  inter- 
mixed with  nitrobenzene.  Certainly  for  medicinal  uses,  at  pre- 
sent, quinoline  offered  for  sale  should  be  presented  with  the  name 
of  its  source. 

a. — Quinoline  is  a  colorless,  mobile  liquid,  transparent  when 
pure,  very  refractive,  and  turning  brown  by  exposure  in  the  air 
and  light.  Specific  gravity,  at  15°  C.,  1.084;  at  20° C.,  com- 
pared with  water  at  same  temperature,  1.094  (SKEAUP,  1881). 
Boiling  point,  231. 5°  C.  (SPALTEHOLTZ)  to  241. 3°  C.  (KEETSCHY, 

1  If  cinchonine  be  C19H22  .  .  .,     2H20=4.99  per  cent,  of  the  sulphate. 
C30Ha4  .  .  .,     2HaO=:4.80 


166  CINCHONA  ALKALOIDS. 

1881).  It  evaporates  slowly  but  completely,  on  exposure^  so 
that  the  oil-spot  it  forms  on  paper  disappears  on  standing.  Crys- 
tallizes in  a  freezing  mixtufe  of  carbon  dioxide  and  ether. — 
The  hydrochloride  crystallizes  in  small  white  nodules ;  the  tar- 
trate  in  rhombic  needles,  forming  under  the  microscope  in  colum- 
nar needles  of  good  length ;  the  salicylate  appears  in  a  reddish- 
gray  powder. 

5. — Quinoline  has  a  pungent,  aromatic  taste,  slightly  resem- 
bling peppermint- oil  in  its  after-taste,  without  bitterness.  It  has 
a  slight  aromatic  odor  like  bitter-almond  oil.  It  is  administered 
in  doses  as  high  as  1  gram  (15  grains)  or  2  grams  (30  grains)  in 
twenty-four  hours  (DONATH,  l$8l)  In  overdoses,  to  animals,  it 
promptly  causes  death  by  asphyxia.1  It  is  strongly  antiseptic  and 
antizymotic.  It  coagulates  albumen  and  myosin  (£>ERENS).  It 
prevents  the  lactic,  not  the  alcoholic,  fermentation  (DONATH).  It 
is  not  found  in  the  urine  after  administration. 

c. — Soluble  in  water,  sparingly  when  cold,  freely  when  hot. 
Soluble  in  all  proportions  in  alcohol,  ether,  and  carbon  disul- 
phide,  and  soluble  in  chloroform,  benzene,  amyl  alcohol,  carbon 
disulphide,  and  in  fixed  and  volatile  oils.  The  salts  of  quinoline 
are  soluble  in  water.  The  tartrate,  (C7H9N)3(C4H6O6)4  (FRIESE, 
BERNTHSEN,  1881),  is  soluble  in  80  parts  of  water  at  16° C.;  in 
150  parts  of  90$  alcohol  at  16°  C. ;  in  350  parts  of  ether.  It 
melts  at  about  125°  C. 

The  hydrochloride,  C9H7N.HC1  (OECHSNER,  1883),  is  soluble 
in  water,  alcohol,  chloroform,  ether,  and  benzene,  in  the  last 
two  solvents  sparingly  in  the  cold.  Melts  at  94°  C.,  and  vola- 
tilizes. 

d. — Quinoline  is  indicated  by  its  odor,  obtained  from  its 
salts  on  addition  of  a  fixed  alkali.  Alkali  hydrates  precipitate 
it,  in  solutions  not  dilute ;  the  precipitate  being  soluble  in  ex- 
cess of  ammonia,  and  easily  taken  into  solution  by  ether,  chlo- 
roform, and  other  solvents  of  the  base.  Solutions  of  quinoline 
salts  are  precipitated  by  the  general  reagents  for  alkaloids. 
According  to  Donath,  the  limits  of  precipitation,  in  certain  favo- 
rable proportions  of  reagents, were  as  follows  :  For  iodine  in  iodide 
of  potassium,  1  to  25000  parts ;  phosphomolybdate,  1  to  25000 
parts ;  mercuric  chloride,  1  to  5000  parts ;  potassium  mercuric 
iodide,  1  to  3500  parts.  The  precipitate  with  phosphomolybdate, 
yellow-white,  dissolves  colorless  in  ammonia ;  with  mercuric 
chloride,  white.  The  precipitate  by  potassium  mercuric  iodide, 

'BERENS,  1885:  Ther.  Gazette,  9,  433. 


,  KAIRINES.  167 

on  adding  hydrochloric  acid,  crystallizes  in  amber-colored  needles. 
No  color  is  caused  by  sulphuric  or  nitric  acid  (DONATH).  By 
long  heating  with  excess  of  sulphuric  acid  quinolirie  sulphonic 
acid  is  formed.  . 

Tests  for  impurities. — In  artificial  quinoline  by  Skraup's 
process,  nitrobenzene  has  been  found  as  an  impurity  (0.  EKIN, 
1882).  The  salts  should  be  completely  soluble  in  water,  the  free 
base  in  water  with  sufficient  acid.  There  should  be  no  bitter 
taste  (impurity  from  cinchonine).  Alkali  hydrates  should  not 
cause  a  colored  precipitate.  Cinchonine-quinoline,  as  prepared 
for  use,  and  unless  repeatedly  distilled  and  recrystallized,  con- 
tains lepidine  (HOOGEWERFF  and  v.  D  ) ;  and  therefore  when 
treated  with  amyl  iodide,  and  then  with  caustic  alkali,  gives  a 
blue  color,  formation  of  a  cyanine  (WILLIAMS),  G^^CgEE-^. 
C10H9NC5H11I. — Aqueous  solution  of  pure  quinoline  salt  [not 
alkaline]  does  not  sensibly  change  the  color  of  permanganate  so- 
lution in  the  first  eight  or  ten  minutes  (HAGER). 

KAIRINES. — Methyl  or  ethyl  substitutions  in  oxy-qumoline- 
tetrahydride,  C9H10(OH)N.  The  methyl  compound  is  C9H9 
(CH3XOH)N=:C10H:13NO  ;  the  ethyl  compound,  C9H9(C3H5) 
(OH)N=C11H15NO.  The  name  kairine  is  used  for  the  hydro- 
chloride.  Oxyhydro-methylquinoline  is  termed  Kairine  M,  and 
oxyhydro-ethylquinoline  Kairine  E  or  Kairoline.  Derivatives 
of  quinoline  (E.  FISCHER,  1883)  of  medicinal  interest.  The  free 
bases  are  not  stable  in  the  air. 

&,  c. — The  methyl  base  crystallizes  in  rhombic  forms ;  is  spar- 
ingly soluble  in  water,  soluble  in  alcohol,  ether,  and  benzene,  and 
acts  as  a  strong  base  in  forming  salts.  It  boils  at  114°  C.  The 
hydrochloride,  C10H13NO .  HCl-l-HsO,  forms  lustrous,  monocli- 
iiic  crystals,  generally  found  in  a  slightly  colored  crystalline  pow- 
der, easily  soluble  in  water.  At  110°  C.  it  loses  its  water  of  crys- 
tallization and  turns  violet.  The  sulphate,  (C10H13NO)2H2SO4, 
forms  lustrous  prisms. 

The  ethyl  base  crystallizes  in  scales  or  plates,  melting  at  76°  C., 
slightly  soluble  in  water,  freely  soluble  in  alcohol,  ether,  and  ben- 
zene ;  hardly  soluble  in  petroleum  benzin.  The  hydrochloride, 
C11H15NO .  HC1,  forms  white  prisms,  generally  appearing  in 
grayish-yellow  crystalline  powder,  freely  soluble  in  water,  spar- 
ingly  soluble  in  hydrochloric  acid. 

b.— The  kairines  have  a  bitter  and  saline,  disagreeable  taste 
and  a  penetrating  odor.  Ordinary  doses  are  one-half  to  one  gram 


168  CINCHONA  ALKALOIDS. 

to  15  grains),  and  doses  of  25  to  50  grains  cause  disturbance.1 
t  is  in  part  excreted  unchanged  in  the  urine  (MERING,  1884), 
The  ethyl  compound  differs  from  the  methyl  compound  only  in 
a  somewhat  longer  duration  of  effect  (Filehne). 

d.— Kairines  are  indicated  by  the  penetrating,  characteristic 
odor  of  the  free  base,  obtained  in  full  from  the  salts  on  adding  a 
fixed  alkali,  and  by  the  bitter  taste.  In  aqueous  or  alcoholic  so- 
lution, treated  with  oxidizing  agents,  as  dichromate  and  an  acid, 
they  give  rosaniline  colors,  violet-blue  to  violet-red,  in  some 
reactions  greenish  tints  being  obtained.  Ferric  chloride  gives 
a  brown  color  in  solutions,  with  gradual  precipitation.  Sodium 
nitrite  in  sulphuric  acid  solution  gives  orange  to  red  colors.  Po- 
tassium ferrocyanide  gives  an  abundant  precipitate ;  phospho- 
tungstic  acid  a  pale  yellow  precipitate.  When  the  base  is  libe- 
rated, as  in  alkaline  solutions,  the  kairines  rapidly  oxidize  in  the 
air,  with  deposition  of  brown,  humus- like  bodies. 

THALLINE.  C10H-,^N"O.  Tetrahydroparaquinanisoil. — A  de- 
rivative of  paraquinanisoil. a  One  of  the  methyl  kairines,  isomeric 
with  "  kairine  M." 

Thalline  appears  in  pale  yellow  crystals,  melting  at  about 
42°  C.,  boiling  at  282°  C.  without  decomposition.  Its  salts  are 
given  in- doses  of  0.25  to  0.75  gram.  It  is  sparingly  soluble  in 
cold,  more  freely  in  hot  water,  and  soluble  in  alcohol,  ether,  and 
petroleum  ether.  It  makes  stable  salts ;  but  in  all  forms  it  is 
easy  to  suffer  change,  and  the  light  affects  it  injuriously.  The 
sulphate  and  tartrate  are  obtained  in  nearly  white  crystals  or  crys- 
talline powder,  melting  at  100°  C.,  with  browning.  The  sulphate 
is  freely  soluble  in  water,  nearly  insoluble  in  ether,  but  is  some- 
what soluble  in  chloroform.  Oxidizing  agents  produce  an  intense 
green  color  with  thalline,  hence  its  name.  Ferric  chloride  is  a 
favorable  oxidizing  agent  for  the  purpose,  giving  a  deep  emerald- 
green  color,  not  changed  by  acidulation  with  sulphuric  acid,  but 
changed  by  reducing  agents. — In  physiological  effect  thalline 
resembles  the  kairines.3 

ANTIPYEINE.  CnH19N2O. — A  proposed  commercial  name  for 
Dimethyl-oxy-quinizine/  C9H6(N.CH3)(CH3)(O)N,  the  hypo- 
thetical base  quinizine  having  the  general  formula  C9H9(NH)]Sr 

'On  use  of  kairine  as  an  antipyretic,  FILEHNE,  1883-1883.  American  uses 
summarized  in  Ther  Gazette,  9,  122  (Feb..  1885). 

2VuLPius,  1883:  Archiv  d.  Phar.,  [31,  22,  840;  Jour.  Chem.  Soc.,  1885, 
Abs.,398,  1022. 

3  BEYER,  1886:  Am.  Jour.  Phar.,  58,  196.     JAKSCH,  1884 


ANTIPYRINE.  169 

(L.  KNOKR,  18841).     Of  interest  for  medicinal  uses  as  an  anti- 
pyretic. 

a. — Antipyrine  crystallizes  in  needles,  melting  at  113°  C.  In 
commerce  it  appears  as  a  white,  crystalline  powder,  sometimes 
slightly  colored. 

b. — Of  a  very  mild  bitter  taste,  not  disagreeable,  and  a  barely 
perceptible  odor.  Dose,  1  to  2  grams  (15  to  30  grains).3  Double 
that  of  quinine  (BUTLER,  1885).  40  to  50  grains  have  caused  se 
rious  effects.  It  appears  in  the  urine  in  about  two  hours  after 
its  administration,  and  can  be  detected  by  applying  the  ferric 
chloride  test  to  the  entire  urine  (CARUSO,  1885). 

c. — Dimethyloxyquinizine  is  very  freely  soluble  in  water,  al- 
cohol, or  chloroform ;  in  about  50  parts  of  ether.  The  aqueou& 
solution  is  neutral  to  test-papers.  Antipyrine  is  a  base  of  some 
strength,  uniting  with  acids  to  form  salts,  from  which  it  is  set 
free  by  the  alkali  hydrates. 

d. — Ferric  chloride  solution  gives  a  decided  red  coloration, 
intense  in  solutions  of  1  to  1000  parts ;  the  color  being  changed 
to  yellow  by  strong  acidulation  with  sulphuric  acid.3  Nitrous 
acid,  as  obtained  by  adding  a  little  potassium  nitrite  and  acidu- 
lating with  dilute  sulphuric  acid,  gives  a  bluish-green  color  in 
dilute,  a  green  crystalline  precipitate  in  concentrated,  solutions — 
characteristic  of  all  the  quinizines  (KNORR).  Two  drops  of  fuming 
nitric  acid,  added  to  2  c.c.  of  a  1  per  cent,  solution  of  antipyrine, 
cause  a  green  color,  and,  after  heating  to  boiling,  another  drop  of 
the  reagent  gives  a  red  color  (Germ.  rh.  Commission).  Tannic 
acid  gives  a  white  precipitate  in  a  1  per  cent,  solution. 

Tests  for  impurities  — The  solution  in  two  parts  of  water 
should  be  neutral,  and  colorless  or  faintly  yellowish,  free  from 
sharp  taste,  and  not  changed  by  solution  of  hydrosulphuric  acid 
(Germ.  Ph.  Commission). 

CINCHONICINE.— See  CINCHONA  ALKALOIDS,  pp.  91,  94. 
CINCHONIDINE.— See  CINCHONA  ALKALOIDS,  pp.  157-161. 

41  The  quinizines  are  derived  from  quinoline  by  the  introduction  of  (NH), 
with  additional  2H,  into  the  quinoline  molecule.  The  (NH)  is  attached  to  the 
N  in  the  ring,  this  N  being  united  to  carbon  by  only  two  bonds,  instead  of 
three  as  in  quinoline.  KNORR:  Ber.  deut.  chem.  Ges.t  17,  546,  2032;  Jour. 
Chem.  Soc.,  1884,  Abs.,  302,  1153,  1377;  Am.  Druggist,  13,  239,  193,  228(1884). 

2  Respecting  physiological  and  therapeutic  effects,  Ther.  Gazette,  1885,  9, 
344,  176,  517.  Also  FILEHNE,  1885:  Zeitsch.  Klin.  Med.,  7;  Am.  Druggist,  13, 
193. 

*  Pharmacopeia  Commission  of  Germ.  Apoth.  Association. 


170  COCA   ALKALOIDS. 

CINCHONINE.— See  CINCHONA  ALKALoros,  pp.  161-165. 
CINCHOTANNIN.— See  TANNINS. 
CINCHOTINE.— See  p.  93. 
CINNAMIC  ACID.— See  p.  69. 

COCA  ALKALOIDS.—  Alkaloids  of  Erythroxylon  Coca 
leaf. 

Cocaine,    C17H211TO4.       The  crystallizable  natural  alkaloid  of 

fresh  coca. 
Ecgonine^  C9H151TO3,  crystallizable.     A  product  of  cocaine  by 

saponification,  and  liable,  also,  to  be  present  in  the  leaf. 
Benzoyl-Ecgonine,  C16H19NO4,  crystallizable.     A  by-product  of 

manufacture  of  cocaine  from  coca.     (Present  in  the  leaf  ? ) 
Anhydride  of  ecgonine,  C9H13ITO2,  crystallizable.     Producible 

from   ecgonine  by  moderately  strong  sulphuric   acid    with 

heat. 
Hygrine,  a  liquid  volatile  alkaloid  (LossEN,  1865)  little  known, 

reported  to  form  crystallizable  salts.     The  existence  of  this 

alkaloid  is  not  established. 
Amorphous  alkaloids  of  coca.      ("  Cocainoidine,  Cocaicine".) 

Said  to  be  obtained  in  preparation  of  cocaine.     Probably 

present  in  the  leaf  in  some  conditions  of  this  article.     Not 

studied. 

Chemical  constitution. — Cocaine,  as  an  easily  saponifiable 
body,  prone  to  split,  by  hydration,  into  ecgonine,  benzoic  acid, 
and  methyl  alcohol,  clearly  has  the  immediate  structure  of  me- 
thyl-benzoyl  ecgonine:  C9H13(CH3) (C7H5O)NO3=C17H21NO4. 
The  saponification  of  cocaine  is  accomplished  by  an  acid  which 
takes  ecgonine  into  combination,  or  by  an  alkali  which  takes 
both  benzoic  acid  and  ecgonine  into  union,  or  even,  it  is  pro- 
bable, by  digestion  with  water,  whereby  benzoyl  and  methyl 
slowly  become  hydroxides.  But  whenever  the  necessary  condi- 
tions are  fulfilled  with  any  saponifying  agent,  the  change  is 
shown  by  the  equation  : 

C9H13(CH3)  (C7H50)N03+2H20 

=C9H15NO3+C7H5O .  OH+CH3 .  OH. 

Ecgonine,  by  loss  of  CO2,  gives  the  constituents  of  a  tropine. 
This  change,  effected  by  distilling  the  barium  compound  of 
ecgonine,  shows  a  not  distant  chemical  relationship  between 


COCA   ALKALOIDS.  171 

cocaine  and  the  atropine  group  of  alkaloids.  And,  like  atro- 
pine, cocaine  in  decompositions  is  liable  to  form  quite  simple 
pyridine  compounds,  showing  a  direct  relation  to  the  pyridine 
series. 

The  saponifieations  of  certain  other  well-known  alkaloids, 
by  digestion  with  alkali,  or  with  acid,  or  with  water,  as  stated  in 
each  instance,  may  be  compared  by  the  following  equations. 
When  the  change  is  effected  by  acids  the  produced  alkaloid  is 
left  in  a  salt  ;  but  when  by  an  alkali,  the  produced  acid  is  left 
in  a  salt.  Ecgonine  unites  both  with  acid  and  with  alkali. 


C17H23NO3  (atropine)  +  H2O=C8H15]SrO  (tropine)  +  C9H10O3 

(tropic  acid). 
^33H43NO13  (aconitine)+H2O=C26H39NOn  (aconine)-|-C7H6O2 

(benzoic  acid). 
C17H01NO4  (cocaine)  +  2H2O=C9H15;N"O3  (ecgonine)  +  C7H6O2 

+CH4O  (meth.  ale.) 
C22H23NO7   (narcotine)  -(-  H2O=C12H15NO3    (hydrocotarnine) 

+CioHio°5  (meconine). 
C32H49NO9  (cevadine)  +  H2O=C27H43NO8  (cevin)  +  C5H8O2 

(methylcrotonic  acid). 
C^H^NOii  (veratrine)  +  H2O=C28H45NO8  (verm)  -f  C9H10O4 

(veratric  acid). 
C17H19NO?  (piperine)  +H2O=C5HnN  (piperidine)  +C12H10O4 

(piperic  acid). 

Except  narcotine  (and  possibly  piperine)  the  sapoiiifiable  alka- 
loids here  given  are  the  representative  medicinal  constituents  of 
the  plants  wherein  they  are  found  :  cevadine  being  the  most 
active  constituent  of  veratrum  veride,  as  veratrine  is  of  cevadilla. 
The  acids  formed  in  the  saponifications  are  aromatic  compounds 
easily  reduced  to  benzoic  acid,  with  the  exception  of  methylcro- 
tonic acid. 

Yield  of  alkaloids  from  coca  leaf.  —  By  the  process  given 
following,  Dr.  Squibb  obtains  from  well  preserved  lots  of  the 
dried  leaves,  shipped  in  bales,  from  0.5  to  0.8  per  cent,  of 
alkaloid.  Dr.  Lyons  obtained  from  the  dried  leaves,  shipped 
in  bales,  0.65  to  6.75,  and  even  0.80,  per  cent,  of  alkaloid.  The 
alkaloidal  product  of  these  assays  consists,  when  good  leaves  are 
taken,  in  the  greater  part  of  crystallizable  alkaloid,  though  in 
some  part  of  amorphous  coca  alkaloids.  The  crystallizable  alka- 
loid is  probably  nearly  all  cocaine  ;  at  least  both  ecgonine  and 
benzoyl-ecgonine  must  be  pretty  surely  left  behind  in  each  meth 
od  of  assay,  by  the  free  solubility  in  water  and  the  very  slight 
solubility  in  ether  of  both  of  these  alkaloids. 


172 


COCA    ALKALOIDS. 


It  is  noteworthy  that  all  the  coca  alkaloids,  natural  or  pro- 
duced, so  far  as  reported,  are  readily  soluble  in  water  as  free  al- 
kaloids, save  only  cocaine  itself.  Also  that  ecgonine  and  ben- 
zoyl-ecgonine  are  nearly  insoluble  in  ether,  which  dissolves 
cocaine  abundantly.  The  solubilities  are  further  shown  here: 


Crystallizdble  : 
Cocaine    

THE  FREE  ALKALOID. 

THE  HTDBOCHLOBIDE. 

Water. 

Ether. 

Water. 

Ether. 

Very  slight. 
Soluble. 
Soluble. 

Not  freely. 
Soluble.  ' 

Soluble. 
Near  in  sol. 
Near  insol. 

Soluble. 
Soluble. 

Soluble. 
Soluble. 
Soluble. 

Soluble. 
Soluble. 

Insoluble. 
Insoluble. 

Ecgonine      

Benzoyl-ecgonine  .... 

Amorphous  : 
"Amorph.  alkaloids." 
Hygrine  

AMORPHOUS  COCAINE.  Cocainoidine.  Cocaicine. — The  qua- 
litative reactions  and  properties  of  the  amorphous  alkaloid  ob- 
tained with  cocaine  in  its  preparation  are  designated  by  A.  B. 
LYONS  1  as  follows :  The  compounds  are  very  difficult  to  crystal- 
lize. The  precipitate  produced  in  the  hydrochlorate  by  alkalies 
did  not  crystallize  at  all  (compare  below  under  Cocaine,  d), 
neither  that  by  picric  acid.  In  very  dilute  solutions  (1  to  5000) 
gold  chloride  produced  after  some  time  minute  prismatic  crys- 
tals, wholly  unlike  in  general  appearance  the  fern-like  forms  from 
the  crystallizable  salt.  Platinum  chloride  produced  a  few  rosette- 
like  aggregations. — On  evaporation  the  amorphous  alkaloid  (pro- 
bably not  free  from  non-alkaloid al  matter)  invariably  turned  dark, 
and  if  the  salt  was  evaporated  quite  to  dryness  it  was  found  to 
be  imperfectly  soluble  in  water. 

ECGONINE.  C9H15NO3=185  (LossEN,  1865).  Crystallizes 
with  1H2O. — A  pyridine  derivative  nearly  related  to  the  tro- 
pines.  The  alkaloidal  body  obtained  by  saponification  of  Cocaine. 
It  crystallizes  from  absolute  alcohol  in  monoclinic  prisms.  Melts 
at  198°  C.,  with  browning,  and  decomposes  at  higher  tempe- 
ratures. Has  a  slight  bitter-sweet  taste.  It  is  freely  soluble 
in  water,  soluble  in  alcohol,  sparingly  soluble  in  absolute  alcohol, 
and  insoluble  in  ether.  In  reaction  it  is  neutral.  It  forms 
slightly  crystallizable  salts  with  hydrochloric  and  other  acids, 


1885:  Am.  Jour.  Phar.,  57,  475. 


ECGONINE.—HYGRINE.  1 73 

gummy  compounds  with  alkalies,  and  a  crystallizable  salt  with 
barium.  The  hydrochloride  of  ecgonine  appears  in  a  yellowish, 
crystalline  mass,  freely  soluble  in  water  and  (Calmels  and  Gos- 
sin)  in  alcohol.  Slightly  soluble  in  alcohol  (Lossen).  Ecgonine 
platinochloride,  (C9H15NO3 .  HCl)2PtCl4 ,  is  soluble  in  water; 
less  soluble  in  alcohol.  The  aurochloride  is  soluble  in  water  and 
in  alcohol.  Barium  salt  of  ecgonine  (CALMELS  and  GOSSIN,  1885) 
forms  slender,  prismatic  crystals,  freely  soluble  in  water  and  in 
alcohol,  slightly  soluble  in  ether. — When  the  barium  salt  of 
ecgonine,  as  obtained,  with  barium  benzoate,  by  saponifying 
cocaine  with  baryta,  is  distilled,  an  isotropine  (C8H15NO)  is 
obtained  (Calmels  and  G.)  It  will  be  observed  that  ecgonine, 
by  loss  of  CO2 ,  presents  the  elements  of  a  tropine. 

BENZOYL-ECGONINE.  C16H19NO4  =  289.  Crystallizes  with 
4H2O.  Union  of  ecgonine  with  benzoic  acid,  the  elements  of 
H2O  being  eliminated:  C9H14JSTO3 .  C7H5O.  (W.  MEKCK,  1885.1 
Z.  H.  SKRAUP,  1885. a) — Found  as  a  by-product  of  cocaine  man- 
ufacture from  coca  leaves.  Crystallizes  in  transparent  flat 
prisms.  When  quickly  heated  melts  [hydrated  ?]  at  90°  to  92° 
C.,  solidifies  again  and  then  melts  [anhydrous?]  at  about  192°  C. 
(Skraup).  Melts,  with  browning,  at  188.5°  to  189°  C.  (Merck). 
Soluble  freely  in  water,  sparingly  in  alcohol,  nearly  insoluble  in 
ether.  It  forms  salts :  the  sulphate  and  acetate  crystallize  in. 
prisms.  The  aurochloride,  C16II19]SrO4 .  HC1 .  AuCl3 ,  forms  yel- 
low scales,  sparingly  soluble  in  water,  soluble  in  alcohol. — On 
heating  benzoyl-ecgonine  with  methyl  iodide  and  an  equal 
volume  of  methyl  alcohol,  the  synthesis  of  cocaine  is  obtained : 
C16H19N04+CH3I  =  C17H21K04 .  HI. 

AN  ANHYDRIDE  OF  ECGONINE.      C9H13NO2.      (CALMELS  and  GoS- 

SIN,  1885.) — When  ecgonine  is  heated  with  moderately  strong 
sulphuric  acid,  an  alkaloid  is  obtained  which  forms  readily  crys- 
tallizable  salts  both  with  acids  and  with  alkalies,  less  soluble  than 
corresponding  ecgonine  salts — the  barium  salt  having  the  compo- 
sition BaO.(C9Et^3NO2)2,  and  its  hydrochloride  forming  stellate 
groups  of  prismatic  needles.  The  platinochloride  forms  feathery 
groups  of  crystals,  very  soluble  in  water  and  in  alcohol. 

HYGRINE.  A  volatile  alkaloid  found  with  cocaine  in  coca 
leaves  (LossEN,  1865  3).  A  thick,  oily  liquid  of  a  pale  yellowish 

1  Ber.  d.  chem.  Oes.,  18,  1594;  Jour.  Chem.  Soc.,  Abs.,  997. 

2  Monatsch.  Chem.,  6,  556;  Jour.  Chem.  Soc.,  Abs.,  1249.    Also  see  PAUL, 
1885:  Phar.  Jour.  Trans.,  [3],  16,  325. 

3W6HLER  and  LOSSEN:  Ann.  Chem.  Phar.,  121,  374;  133,  352.  LOSSEN: 
"Dissertation." 


174  COCAINE. 

color.  Distils  slowly  with  water ;  distils  alone  between  140°  C. 
and  230°  C.  It  has  an  odor  resembling  trimethylamine,  and  a 
burning  taste.  Had  no  poisonous  effect  on  rabbits.  It  is  solu- 
ble in  water  (not  in  all  proportions) ;  freely  soluble  in  alcohol  and 
in  ether.  It  unites  with  acids,  forming  salts.  The  hydrochloride 
forms  deliquescent  crystals.  It  is  precipitated  by  iodine  in  po- 
tassium iodide  solution,  mercuric  chloride,  silver  nitrate,  and 
stannous  chloride. 

COCAINE.  C17H21IsrO4=303  (LossEN,  1865).  Chief  alka- 
loid of  the  Erythroxylon  coca  leaf  (^IEMANN,  1860). — For  the 
yield  from  the  leaf,  and  for  chemical  constitution  and  relations 
of  the  alkaloid,  see  above  under  COCA  ALKALOIDS. 

Cocaine  is  identified  by  its  effect  on  the  tongue  or  eye  (5), 
and  the  agreement  of  its  precipitations  (d).  It  is  distinguished 
from  ecgonine  or  beiizoyl-ecgonine  by  solubilities  of  the  free  al- 
kaloid in  water  and  in  ether  (g).  Its  separations  are  effected  by 
use  of  ether,  etc.,  and/r^m  coca  leaf\>y  several  assay  methods  (<?). 
Estimation,  gravimetrically  or  volumetrically  (f] ;  also  by  ob- 
taining limits^  of  precipitations  (d).  Tests  for  impurities  (g). 

a. — Cocaine  crystallizes  in  monoclinic  prisms,  obtained  from 
concentrated  alcoholic  solution.  It  appears  either  in  colorless, 
distinct  crystals  or  in  a  white,  crystalline  or  granular  powder. 
The  alkaloid  imperfectly  purified  from  the  leaf,  or  that  from  in- 
jured leaves,  is  more  or  less  dark  colored,  and  contains  amorphous 
coca  alkaloid,  partly  liquid.  Cocaine,  free  alkaloid,  is  often  pre- 
sented as  an  amorphous  powder,  cohering  like  magnesia  (SQUIBB), 
and  not  quite  white. — The  salts  are  more  crystallizable  than  the 
free  alkaloid.  The  hydrochloride  crystallizes  with  a  general  ap- 
pearance like  that  of  the  free  alkaloid ;  from  concentrated  alco- 
holic solution  in  short,  rough  prisms,  among  which  rhombic  plates 
may  be  found  under  the  microscope  ;  from  dilute  alcoholic  solu- 
tion long,  brittle  needles  are  obtainable  ;  from  aqueous  solution, 
silky-lustrous  needles.  The  hydrobromide  crystallizes  in  color- 
less, radiating  needles. — The  hydrochloride  is  the  chief  form  of 
the  alkaloid  in  general  use.  It  is  furnished  in  different  styles, 
including  hydrated  crystals  of  good  size,  minute  anhydrous  crys- 
tals, granules  of  obscurely  crystalline  powder,  and  amorphous 
powder. 

Cocaine  melts  at  98°  C.  (LOSSEN).  More  strongly  heated  it 
vaporizes  with  decomposition  of  the  greater  portion.  The  hydro- 
chloride  parts  with  its  water  of  crystallization  (2  aq. )  at  or  below 
100°  C. 


COCAINE.  175 

b. — Cocaine  lias  a  bitter  taste,  and, is  without  odor.  Its  de- 
composition products  in  mouldy  coca  leaves  are  said  sometimes 
to  present  a  tobacco-like  odor. — Cocaine  is  distinguished  by  an 
intense  local  ansesthetic  and  blanching  effect  upon  the  mucous 
membrane,  giving  on  the  tongue  a  characteristic  insensibility,  a 
sudden  cessation  of  feeling,  lasting  but  a  few  minutes  (NIEMANN, 
1860).  One  drop  of  a  four  per  cent,  solution  (about  0.04  grain) 
suffices  to  blanch  the  conjunctiva  of  the  eye  ; l  and  by  the"  same 
application  to  the  tongue  (previously  rinsed  clean)  iirst  the  slight 
bitterness  and  then  a  decided  numbness  are  perceived.  These 
effects  are  evanescent,  unless  the  application  be  repeated.  The 
anaesthesia  of  an  eye,  for  surgical  operations,  can  be  accomplished 
by  the  application  of  "  5  drops  of  a  4  per  cent,  solution  in  two 
installations  ten  minutes  apart"  (E.  R.  SQUIBB,  1885). — Dilatation 
of  the  pupil  of  the  eye  is  a  general  effect  of  cocaine,  either  ap- 
plied to  the  eye  or  administered  to  the  system.  This  effect  is 
said  not  to  be  invariable ;  certainly  the  midriasis  from  cocaine  is 
very  far  from  reaching  the  intensity  obtained  by  the  atropine 
group  of  alkaloids.  I^IKOLSKY  obtained  with  warm-blooded  ani- 
mals a  constant  widening  of  the  pupil  when  under  the  action  of 
cocaine.  Dilatation  was  also  observed  with  frogs. 

The  fatal  dose  of  cocaine  was  found  for  dogs,  by  DANINI 
(1873),  0.15  to  0.30  gram  (2£  to  4|  grains).  In  rabbits  the  hy- 
podermic administration  of  0.1  gram  (1-J  grain)  per  kilogram  of 
body- weight  caused  death  in  a  few  hours,  sometimes  in  a  few 
minutes  (v.  ANREP,  1880).  The  hypodermic  introduction  of 
about  ^V  grain  caused  dangerous  symptoms  in  a  girl  of  12  years 
(Ther.  Gazette,  Feb.,  1886,  p.  88). 

c. — Cocaine  is  very  slightly  soluble  in  water,  soluble  in  alco- 
hol, ether,  chloroform,  benzene,  petroleum  benzin,  disulphide  of 
carbon,  and  in  fixed  and  volatile  oils. — The  salts  of  cocaine  are 
soluble  in  water  and  in  alcohol.  The  hydrochloride  dissolves  in 
less  than  its  own  weight  of  water ;  is  freely  soluble  in  alcohol, 
less  readily  in  absolute  alcohol  and  in  chloroform,  and  is  practi- 
cally insoluble  in  ether,  in  petroleum  benzin,  and  in  fixed  and 
volatile  oils. — Cocaine  solutions  have  a  strongly  alkaline  reaction 
with  litmus  (not  affecting  phenol-phthalein),  and  form  definite 
salts.  The  hydrochloride  and  hydrobromide  are  neutral  in  reac- 
tion. HydroMoride  crystals  are  permanent  in  the  air ;  obtained 

1  This  specific  use  of  cocaine  was  first  announced  by  Dr.  Carl  Koller,  of 
Vienna,  at  Heidelberg,  in  September,  1884  (London  Lancet,  1884,  p.  990). 
(v.  ANREP,  1880;  SCHROFF,  1862.)  The  extensive  use  of  cocaine  as  a  local  anaes- 
thetic rapidly  followed  the  announcement  of  Dr.  Koller. 


176  COCAINE. 

in  presence  of  water  they  have  two  molecules  (9.6  per  cent.)  of 
water  of  crystallization,  but  anhydrous  crystals  can  be  obtained 
from  alcohol.  Hydrobromide  crystals  also  contain  two  molecules 
(8. 57  per  cent.)  of  water  of  crystallization.  Cocaine  citrate  is 
hygroscopic  and  does  not  easily  crystallize.  The  oleate  of  cocaine 
readily  crystallizes,  and  dissolves  in  oleic  acid  or  in  oils  (LYONS). 
Aqueous  solutions  of  cocaine  salts  after  a  few  days  suffer  decom- 
position of  the  alkaloid,  with  vegetable  cell  growths,  unless  pre- 
served by  an  antiseptic  (SQUIBB,  1885).  Neutral  solution  of  the 
hydrochloride  in  freshly  prepared  distilled  water,  when  secluded 
from  the  air  in  glass-stoppered  bottles,  keeps  unchanged  several 
months  (POLENSKI,  1885). 

d. — The  local  physiological  test  upon  the  tongue,  and  then 
upon  the  eye,  for  the  (evanescent)  effects  above  detailed,  may  be 
resorted  to  for  identification.  If  the  material  tested  be  known 
only  as  alkaloidal  matter,  safety  requires  that  the  substance  should 
be  obtained  in  neutral  solution  of  definite  strength,  the  prelimi- 
nary trials  being  made  with  such  attenuations  as  would  be  harm- 
less in  case  of  the  presence  of  aconitine  or  atropine,  or  other 
agent  of  most  intense  action.  In  the  experiments  of  DR.  SQUIBB 
(1887)  a  distinct  impression,  just  short  of  numbness,  was  ob- 
tained by  three  out  of  four  persons  by  holding  one  minute  in  the 
mouth  YJ-j.  grain  (0.00063  gram)  of  cocaine  in  solution  in  one 
minim  of  water,  the  mouth  having  been  previously  rinsed.  When 
the  solution  of  alkaloid  was  dried  on  filter-paper,  the  limit  of  re- 
cognition was  found  to  lie  at  j^oir  °f  a  grain  of  the  alkaloid,  held 
in  the  mouth  one  minute  (Ephemeris,  3,  918). 

Mayer's  solution  gives  a  precipitate  with  cocaine  hydrochlo- 
ride. According  to  LYONS  (1885)1  the  precipitate  is  visibly  pro- 
duced in  one  drop  of  a  solution  of  the  salt  in  12500  parts  of 
water.  Precipitates  in  very  dilute  solutions  are  formed  by 
iodine  in  potassium  iodide  solution,  by  phosphomolybdate, 
and  by  tannin.  Mercuric  chloride  causes  a  precipitate  in  quite 
concentrated  solutions,  with  a  resulting  red  color  like  that  of 
atropine  (FLUCKIGER,  1886).  Caustic  alkalies,  including  ammo- 
nia, added  to  moderately  dilute  solutions,  cause  a  precipitation  of 
the  free  alkaloid.  The  precipitate  has  a  crystalline  structure, 
either  from  the  first  or  after  standing  a  short  time.  Excess  of 
ammonia  does  not  dissolve  the  precipitate,  but  any  considerable 
excess  of  fixed  alkali  will  soon  bring  about  saponification  of  the 
alkaloid,  with  partial  solution.  The  alkali  carbonates  and  bi- 

1  Am.  Jour.  P/iar.,  57,  473. 


COCAINE.  177 

carbonates  cause  precipitation. — Platinum  chloride  and  Gold 
chloride  produce  crystalline  precipitates,  the  former  reaction  re- 
quiring moderate  concentration 

Cocaine  has  a  good  degree  of  reducing  power.  Ferricya- 
nide  paper,  prepared  by  wetting  blotting-paper  with  a  drop  or 
two  of  a  fresh  mixture  of  equal  volumes  of  potassium  ferricya- 
nide  and  ferric  chloride  solutions,  on  adding  a  drop  or  two  of 
the  alkaloid  solution  and  shading  from  the  light,  gives  reduction 
to  the  blue  in  the  following  ratio  (CuiiTMAN,  1885 ') :  With  mor- 
phine in  J  minute ;  cocaine,  1J  minute ;  brucine,  6  m.  ;  quinine, 
7  m. ;  cinchonine,  10  m.  ;  strychnine,  veratrine,  each  15  minutes. 
Permanganate  of  potassium  is  but  slightly  reduced  at  once, 
fully  on  standing  or  on  boiling,  and  in  concentrated  cocaine  solu- 
tions decinormal  solution  of  permanganate  produces  a  crystalline 
precipitate  of  cocaine  permanganate,  appearing  under  the  mi- 
croscope when  fresh  in  beautiful  violet-red  crystals,  rhombic 
nearly  rectangular  plates,  frequently  grouped  in  rosettes.  (F. 
GIESEL,  1886;  A.  B.  LYONS,  1886).  A  brown  residue  of  man- 
ganic hydrate  is  soon  formed  (see  g). 

Saponrfication  of  cocaine  was  accomplished  by  LOSSEN  (1865) 
with  hydrochloric  acid  in  hot  digestion  (100°  C.),  best  in  sealed 
tubes,  continuing  the  digestion  as  long  as  the  precipitation  of 
ben  zoic  acid  is  seen  to  increase.  MACLAGEN  (1885  a)  caused  a 
saponification  with  alcoholic  potash,  or  the  cocaine  "  was  dis- 
solved in  alcohol  and  strong  solution  of  soda  or  potassa  added," 
when  "  the  odor  of  benzoic  acid  is  quickly  perceptible,"  soon 
disappearing.  After  a  short  time,  if  a  little  water  be  added,  the 
alcohol  driven  off  by  a  gentle  heat,  and  the  liquid  acidulated,  a 
precipitate  of  benzoic  acid  is  obtained.  Ammonia  appeared  to 
effect  no  saponification.  CALMELS  and  GOSSIN  (1885)  effected 
the  saponification  by  barium  hydrate,  in  sealed  tubes,  at  120°  C. 
The  products  are  ECGONINE,  Benzoic  Acid,  and  Methyl  Alcohol : 
C17II21]Sr04+2H20=rC9H15N03+C7H602+CH40.  By  boiling 
in  water,  especially  by  long  hot  digestion,  cocaine  suffers  saponi- 
fication, and  its  solutions  redden  litmus  (PAUL,  1886;  FLUCK- 
IGER,  1886). 

e. — Separations. — Cocaine  is  removed  from  aqueous  solu- 
tions of  its  salts  by  adding  ammonia  to  liberate  the  alkaloid, 
avoiding  an  excess,  and  shaking  out  with  ether,  chloroform,  ben- 
zene, or  petroleum  benzin.  From  ethereal  solutions  the  alkaloid 
is  taken  up  by  slightly  acidulated  water,  upon  agitation. 

lPhar.  Rundschau,  3,  252. 

2  The  American  Druggist,  14,  23  (Feb.,  1885). 


178  COCAINE. 

From  the  coca  leaves,  the  following  process  is  used  by  LYONS  :* 
Take  10  grains  of  No.  30  powdered  coca  leaves,  or  so  much  of 
this  powder  as  will  represent  10  grains  of  a  sample  of  leaves 
carefully  selected  from  toward  the  centre  of  the  package.  Place 
in  a  bottle  of  capacity  of  about  120  c.c.,  add  100  c.c.  of  a  mix- 
ture of  95  volumes  stronger  ether  and  5  volumes  of  a  spirit  of 
ammonia  made  by  mixing  1  volume  ammonia-water  of  sp.  gr, 
0.9094  with  19  volumes  absolute  alcohol,  stopper  securely,  and 
agitate  well  at  intervals  of  half  an  hour  for  a  day.  Allow  as 
nearly  as  possible  24  hours  for  the  maceration  :  a  perceptible  loss 
of  the  alkaloid,  doubtless  due  to  the  free  alkali,  results  from  ma- 
cerating over  48  hours.  Take  out  quickly  50  c.c.1  of  the  clear 
ethereal  liquid  into  a  separator.  If  there  are  floating  particles, 
filter  through  a  small  filter,  and  wash  with  least  sufficient  quan- 
tity of  ether.  Add  in  the  separator  5  c.c.  of  acidulous  water 
containing  -fa  by  volume  of  sulphuric  acid.  Agitate  well,  allow 
the  acid  liquid  to  separate,  draw  the  aqueous  layer  off  into  a  bot- 
tle of  the  capacity  of  30  c.c. ;  add  again  in  the  separator  2-J  c.c. 
of  water  slightly  acidulated  with  sulphuric  acid,  shake  out,  leave 
to  separate,  and  draw  off  ;  and  repeat  this  washing  once  or  twice 
more,  receiving  all  the  aqueous  portions  together.  To  the  whole 
aqueous  liquid,  in  the  bottle,  add  10  c.c.  of  ether,  agitate, 
leave  at  rest,  pour  off  the  ethereal  wash-liquid,  add  in  the  bottle 
10  c.c.  of  fresh  ether,  then  gradually  add  a  slight  excess  of  dry 
carbonate  of  sodium,  with  care  to  avoid  loss  by  effervescence, 
cork  securely,  agitate  well  but  not  so  violently  as  to  cause  emul- 
sification,  set  at  rest,  and  with  a  rubber- bulb  pipette  draw  off  the 
clear  ethereal  layer  into  a  small  tared  beaker,  to  be  now  set  in  a 
warm  place  (about  45°  C.,  113°  F.)  While  the  ether  is  evaporat- 
ing wash  with  a  second  and  third  portion  of  ether,  and  wash  with 
ether  until  a  drop  of  the  aqueous  fluid,  acidulated,  and  treated 
with  a  minute  drop  of  Mayer's  solution,  gives  not  more  than  a 
slight  milkiness.  The  residue  left  by  evaporation  of  the  ether 
is  inspected,  and  dried  at  100°  C.  to  a  constant  weight.  The  al- 
kaloid obtained  represents  5  grams  of  coca  leaves.  The  percen- 
tage is  obtained  by  dividing  the  milligrams  of  weight  by  50. 

The  assay  of  coca  leaves  is  conducted  by  Dr.  E.  R.  SQUIBB  2 
as  follows  :  Of  the  coarsely  powdered  leaves  100  grams  are  mois- 
tened with  100  c.c.  of  water  containing  5$  of  sulphuric  acid,  and 
packed  moderately  close  in  a  cylindrical  percolator.  Using  the 
same  acid  solvent,  500  c.c.  of  percolate  are  obtained,  better  by 
the  help  of  a  pump.  The  percolate  is  well  mixed  in  a  large 

1 1885:  Chicago  Pharmacist,  Sept.        2  Ephenwris,  3,  912  (Jan.,  1887). 


COCAINE.  179 

• ' '    4? 

beaker  with  50  c.c.  of  kerosene,  when  enough  well-crystallized 
carbonate  of  sodium  to  saturate  500  c.c.  of  acid- water  is  gra- 
dually  added,  the  requisite  quantity  having  been  previously  de- 
termined by  a  trial  upon  100  c.c.  of  the  acidulated  water,1  Dur- 
ing four  or  live  hours  of  digestion  the  mixture  is  repeatedly 
stirred.  The  kerosene  is  drawn  off  by  a  separator  or  a  small 
siphon.  The  extraction  is  continued  with  two  additional  por- 
tions each  of  25  c.c.  of  kerosene.  If  a  layer  of  emulsion  appears 
it  is  drawn  off  separately,  and  stirred  with  asbestos,  or  sand,  or 
dry  filter  paper  pulp,  and  the  separated  kerosene  added  to  the 
larger  portion.  If  the  mixture  have  been  shaken  instead  of 
stirred,  the  most  of  the  kerosene  will  be  found  in  emulsion.2 

The  kerosene  solution  of  alkaloid  (100  c.c.)  is  shaken  vigo- 
rously, in  a  separator,  with  two  portions  of  10  c.c.  of  the  acid- 
water,  and  one  portion  of  5  c.c.  of  the  same.  Now  to  the  25  c.c. 
of  cocaine  sulphate  solution  10  c.c.  of  stronger  ether  are  added,  in 
a  separator,  and  well  shaken,  then  a  moderate  excess  of  sodium 
carbonate  crystals  is  added.  After  the  effervescence  the  mix- 
ture is  shaken,  the  ether  separated,  and  two  more  washings  are 
made,  each  with  10  c.c.  of  the  ether.  The  collected  ether,  per- 
fectly free  from  aqueous  solution,  is  evaporated  in  a  weighed 
beaker  of  at  least  three  times  the  capacity  of  the  ether.  The 
alkaloid  will  be  in  form  of  a  light  amber-colored  varnish.  As 
soon  as  the  ether  is  wholly  evaporated  the  beaker  is  cooled  and 
weighed,  and  the  tare  subtracted.  The  highest  yield  obtained 
by  J)r.  Squibb  has  been  0.892$.  On  standing  24  to  48  hours 
the  varnish-coat  of  alkaloid  is  converted  into  a  white,  crystal- 
line crustr  without  change  of  weight. 

TBUPHEME  (1885)  recommends  an  assay  plan  as  follows :  The 
coca  leaves  are  exhausted  with  ether ;  after  recovering  the  ether 
by  distillation,  the  residual  extract  is  treated  with  boiling  water, 
mixed  with  magnesia,  and  dried.  The  dried  mass  is  exhausted 
with  amyl  alcohol. 

In  all  assay  operations  the  continued  action  of  hot  acids,  or 
hot  fixed  alkalies,  or  even  of  hot  water,  is  to  be  avoided,  as  liable 
to  cause  saponification  or  other  alterations. 

f. —  Quantitative. — Cocaine  is  estimated  gravimetrically  by 

1  Excess  of  alkali  is  required,  and  sufficient  excess  is  obtained  by  following 
the  direction. 

2  Further  assurance  of  the  complete  separation  of  the  alkaloid  is  obtained 
by  adding  a  little  more  sodium  carbonate  and  shaking  out  with  ether  (25  c.c.), 
when  the  residue  by  evaporation  of  the  ether  may  be  tested  on  the  tongue  for 
cocaine. 


i8o  COCAINE. 

drying  at  near  100°  C.,  and  weighing  as  anhydrous  alkaloid 
(see  a).  Volumetrically,  cocaine  may  be  estimated  with  Mayer's 
solution,  standardizing  the  reagent  by  a  known  solution  of  the 
alkaloid,  and  correcting  the  result  by  parallel  titrations  of  the 
known  solution  and  that  under  estimation,  concentration  being 
the  same  in  each  (p.  45). 

g. — Tests  for  purity. — For  the  next  revision  of  Ph  Germ, 
the  following  requirements  for  cocaine  hydrochloride  are  pro- 
posed : '  A  white,  crystalline  powder  of  faintly  acid  reaction, 
somewhat  bitter  taste,  and  causing  a  very  characteristic  insensi- 
bility of  the  tongue,  intense  but  transient Concentrated 

sulphuric  acid  dissolves  it  with  some  foaming  but  without  colora- 
tion, and  no  color  is  caused  by  solution  in  nitric  or  hydrochloric 
acid.  The  salt  should  dissolve  in  twice  its  weight  of  cold  water ; 
and  when  "heated  on  platinum  foil  should  leave  no  residue. — The 
Br.  Ph.  designates  that  the  salt  "  dissolves  without  color  in  cold 
concentrated  acids,  but  chars  with  hot  sulphuric  acid."  Also, 
"  the  solution  yields  little  or  no  cloudiness  with  chloride  of 
barium  or  oxalate  of  ammonium."  Some  incidental  impuri- 
ties give  yellow  to  red  and  rose-red  colors  with  the  cold  sul- 
phuric acid,  which  is  said  to  be  a  severe  but  quite  general  test  of 
purity. 

Tests  l}y  solubilities  (see  table  under  Coca  Alkaloids)  of  the 
free  alkaloid.  May  be  applied  to  cocaine  salts  by  treating  with 
dilute  ammonia,  avoiding  much  excess,  draining,  and  washing  with 
a  very  little  water,  when  the  precipitate  may  be  dried  at  a  gentle 
heat  and  used  for  the  tests.  The  free  cocaine  should  require  not 
less  than  1200  to  1800  times  its  weight  of  cold  water  to  dissolve 
it  (absence  of  any  considerable  proportions  of  ecgonine  or  ben- 
zoyl-ecgonine).  Should  also  be  completely  soluble  in  ether.  But 
for  this  test  cocaine  salts  and  any  ammonium  salt  should  be  well 
removed. 

According  to  the  excellent  investigation  of  DR.  SQUIBB  (1887, 
\Ephemeris,  3,  906),  the  cocaine  of  commerce  consists  mainly  of  a 
larger  portion  of  readily  crystallizable  salt  with  smaller  varying 
proportions  of  difficultly  cry  stall  izabie  salt.  The  latter  portion 
was  found  not  to  be  inferior  in  physiological  power.  Further, 
solubility  in  chloroform  was  found  a  trusty  indication  of  the  pro- 
portion of  the  less  crystallizable  part,  this  requiring  less  chloro- 
form to  dissolve  it.  0.4  gram  of  perfectly  crystallizable  hydro- 
chloride  takes  9  c.c.  of  chloroform  of  not  less  than  1.47  sp.  gr.  to 
dissolve  it.  The  salt  is  precipitated  from  chloroformic  solutions 

1  The  pharmacopceial  commission  of  the  Deutschen  Apotheker-verein,  1885. 


COLORING  MATERIALS.  181 

by  adding  ether. — The  same  investigator  reports  the  "perman- 
ganate test  of  Giesel  to  be  hypercritical  and  often  fallacious." 

CODAMINE.— See  OPIUM  ALKALOIDS. 
CODEINE. — See  OPIUM  ALKALOIDS. 

COLORING  MATERIALS.— The  scope  of  this  work  does 
not  permit  giving  the  descriptive  chemistry l  of  the  dye-stuffs  and 
pigments  in  use  at  present.  Several  systematic  methods  of  analy- 
sis of  coloring  matters,  recently  contributed  by  color  chemists,  are 
presented  in  the  following  pages.  To  these  schemes  for  qualita- 
tive analysis  some  notes  of  description  or  of  definition  of  color 
compounds  are  added,  and  references  to  convenient  sources  of 
descriptive  literature  are  given.  A  list  of  published  schemes  of 
analysis  of  coloring  matters  is  here  offered,  with  the  assurance 
that  it  is  by  no  means  a  complete  bibliography  of  methods  of 
qualitative  work  upon  colors. 

THE  CHEMICAL  DETERMINATION  OF  COMMERCIAL  COLORING- 
MATERIALS.  By  treatment  of  the  dye-stuffs  alone,  or  of  tissues 
colored  by  them. 

For  Blue  coloring  matters:  vegetable  blues,  coal-tar  blues,  and  prussian  blue. — 
W.  STEIN,  1869:  Polyt.  Centralbl.,  p.  1023;  Zeitsch.  anal.  Chem.,  9,  128. 

For  Red  coloring  materials,  mainly  those  of  vegetable  origin. — W.  STEIN,  1870. 
Given  on  pages  188  to  192  of  this  work,  with  addition  of  notes  and  refer- 
ences. A  ready  method. 

For  Violet  colors,  both  those  of  vegetable  origin  and  coal-tar  derivatives. — W. 
STEIN,  1870:  Polyt.  Centralbl.,  p.  1504;  Zeitsch.  anal.  Chem.,  10,  375. 

1  The  following  references  may  be  of  some  service  to  those  in  search  of 
literature  upon  the  descriptive  chemistry  of  color  substances: 

POST'S  "  Chemisch-Technische  Analyse,"  Braunschweig,  1882.  Pages  963 
to  997:  "  Farbstoffe  und  zugehorige  Industrieen."  Natural  organic  colors:  ar- 
tificial colors,  both  mineral  and  organic. 

BOCKMANN'S  "Chemisch-Technische  Untersuchungs-Methoden,"  Berlin, 
1884.  Pages  245  to  336:  "  Theerfarben,"  von  Dr.  R.  NIETZKI.  Pages  337  to  343: 
"  Ultramarin,"  von  Dr.  E.  BUCHNER. 

HAGER'S  "Pharm.  Praxis,"  Erganzungsband,  1883.  Pages  951  to  987: 
"Pigmenta." 

SLATER'S  "Colors  and  Dye-Wares,"  London,  1879,  pp.  217.  Serviceable 
only  for  commercial  definitions. 

CROOKES,  1882:  "Dyeing  and  Tissue  Printing,"  London. 

"Bleaching,  Dyeing,  and  Calico  Printing."  Published  by  J.  and  A. 
Churchill,  London,  1883.  With  an  account  of  Dye- Wares 

ROSTER,  1882:  "  The  Hygiene  of  Coal-Tar  Colors,"  Heidelberg.  A  full  re- 
view *fn  Chem.  News,  48,  20. 

WITZ,  Relation  of  Colors  to  Cellulose,  1884:  Ding.  pol.  Jour.,  250,  271: 
Jour.  Soc.  Chem.  Ind.,  3,  206. 


1 82  COLORING  MATERIALS. 

For  Greens  and  Yellows,  from  vegetable  sources  and  from  coal-tar. — W.  STEIN, 
1870:  Polyt.  Centralbl.,  p.  1055;  ZeitscJi.  anal.  Chem.,  10,  115. 

For  all  the  Colors,  mainly  those  of  coal-tar  production. — OTTO  N.  WITT,  1886. 
In  the  next  following  pages,  with  addition  of  brief  definitions  of  commer- 
cial names.  A  quite  elaborate  scheme,  presented  by  a  chemist  well  known 
for  important  contributions  on  the  chemistry  of  coal-tar  dyes. 

For  Colors  in  general,  mostly  of  vegetable  origin. — F.  FOL,  1874.  Given  in 
the  following  pages. 

For  the  Coal- Tar  Colors,  as  fixed  upon  Silk,  Wool,  and  Cotton.— N.  BIBANOW, 


1875:  Monit.  scientif.,  [3],  4,  509;  Zeitsch.  anal.  Chem.,  14,  106. 
Veg 

News,  46,  217  (in  full):  Jour.  Soc.  Chem.  Ind.,  i,  447  (in  full). 


For  Coal-Tar  Colors  and   Vegetable  Colors,  as  fixed  upon  fabrics. — J.  JOFFRE, 
1882:  Monit.  scientif.,  [31,  12,  959;  Zeitsch.  anal.  Chem.,  22,  610;  Chem. 
.1);  Joi 


For  Coal- Tar  Dye-Stuffs. — BOCKMANN'S  "  Chemisch-Technische  Untersuchungs- 
Methoden,"  1884,  pp.  328-333. 

For  the  Principal  Colors,  taken  as  free  dye-stuffs  or  in  solutions. — DRAGEN- 
DORFF,  in  "Gerichtl.  Chem.  Organ.  G'ifte,"  1872.  Given  in  this  work  in 
pages  following.  Presents  a  method  of  separation  by  the  immiscible  sol- 
vents. 

For  Colors  in  General,  fixed  upon  dyed  and  printed  fabrics. — CROOKES'S  "Dye- 
ing and  Tissue  Printing,"  1882,* p.  399. 

For  Coal-Tar  Colors.— J.  SPILLER,  1880:  Chem.  News,  42,  191. 

WITT'S  PLAN  OF  QUALITATIVE  ANALYSIS  OF  COMMERCIAL  COLOR- 
ING MATTERS/  chiefly  Coal  Tar  Dyes. 

A. — Red  Coloring  Matters. 

I.  The  color  is  insoluble  in  cold,  and  with  difficulty  soluble 
in  hot  water,  but  it  is  easily  dissolved  by  alcohol. 

1.  The  alcoholic  solution  is  salmon-colored,  without  fluorescence.     The  so- 
lution in  strong  sulphuric  acid  is  reddish-violet. — Naphthalene-Carmine  (Kar- 
min-naphte) 

2.  The  alcoholic  solution  is  reddish  blue,  and  shows  an  intense  orange-red 
fluorescence.     Examined  with  the  spectroscope,   it  shows  a  wide  absorption- 
band,  which  completely  extinguishes  the  yellow  and  green  portions  of  the  spec- 
trum.2    The  solution  in  sulphuric  acid  is  greenish-gray.     On  diluting,  the  solu- 
tion first  turns  red.  and  then  a  reddish-violet  precipitate  is  formed. — Magdala- 
Red  (Naphthalene- Red.     Rosenaphthalene). 

3.  Insoluble  in  cold  water,  slightly  soluble  in  hot.     The  behavior  of  the  al- 
coholic solution  is  precisely  similar  to  magdala-red,  only  the  absorption-band 
is  more  to  the  right,  so  that  a  portion  of  the  yellow  remains  visible.     The  solu- 
tion in  sulphuric  acid  is  colorless;  on  diluting,  each  drop  of  water  as  it  enters 
the  liquid  causes  a  deep  red  color.     By  the  further  addition  of  water  the  whole 
liquid  is  colored  a  deep  magenta-red.     This  reaction  is  different  from  that  of 
magdala-red. — Quinoline-Red. 

4.  The  alcoholic  solution  fluoresces  in  a  similar  manner,  but  the  fluores- 
cence is  greener.     The  solution  in  concentrated  sulphuric  acid  is  lemon-colored 
to  orange,  and  shows  no  striking  change  of  color  on  the  addition  of  water. — - 


'Otto  N.  Witt,  1886:  Tlie  Analyst,  n,  111  (translated  by  J.  T.  Leon). 
Not  including  anthracene  products.  * 

2  A  good  pocket  spectroscope,  which,  with  ordinary  adjustment,  will  show 
Fraunhofer's  lines,  is  sufficient  for  the  examinations  in  this  scheme. 


WITTS  PLAN  OF  ANALYSIS.  183 

Eosins  (tetrabromfluoresceins,  C2oH8Br405),  soluble  in   alcohol  (to  be  distin- 
guished from  each  other  by  the  difference  in  tint  of  dyed  specimens). 

5.  The  alcoholic  solution  is  a  dull  bluish-red.  The  solution  in  strong  sul- 
phuric acid  is  green,  on  dilution  becoming  bluish-red. — Rhodidine  (Induline  of 
the  naphthalene  group). 

II.  The  coloring  matter  is  more  or  less  soluble  in  cold  water, 
easily  soluble  in  boiling  water. 

a.— The  solution  is  precipitated  by  soda. — Basal  coloring 
matters. 

1.  The  solution  in  water  is  bluish-red,  changing  on  the  addition  of  hydro- 
chloric or  sulphuric  acid  to  a  yellowish- brown.     The  red  color  is  restored  by 
the  addition  of  sodium  acetate.     By  boiling  wool  in  a  dilute  ammoniacal  solu- 
tion which  has  only  a  slight  red  color,  it  is  dved  a  deep  red.      Zinc-dust  per- 
manently decolorizes  the  aqueous  solution.     The  solid  is  either  in  the  form  of 
green  crystals  or  has  the  appearance  of  a  green  metallic  powder,  which  dis- 
solves in  sulphuric  acid  to  a  yellowish-brown  solution. — Magenta  (Fuchsin,  Ro- 
saniline  monacid  salts,  p.  191) 

2.  The  solution  is  bluish-red.    Ammonia  gives  an  orange-colored,  flocculent 
precipitate,  which  dissolves  in  ether  to  a  red  solution  with  a  red  fluorescence. 
The  solution  in  sulphuric  acid  is  green;    on  diluting  with  water  the  color 
changes  to  blue  or  violet,  and  finally  to  red. — Toluylene-Red  (Ci5Hi6N4)  (known 
in  commerce  as  neutral  red,  generally  very  impure,  and  therefore  not  giving 
pure  colors  in  the  above  reactions). 

5. — The  solution  is  not  precipitated  by  soda.  Acid  coloring 
matters,  or  "basal  colors  of  the  Saffranin  class  of  compounds 
(type  C18H14N4). 

1.  On  the  addition  of  soda  to  the  aqueous  solution  a  change  of  color  takes 
place,  the  solution  becoming  colored  an  intense  blue.    The  solution  in  sulphuric 
acid  is  a  brownish-yellow,  becoming  somewhat  redder  on  dilution. — Oallein 
{Pyrogallol-phthalein,  C20Hi 007). 

2.  By  the  addition  of  alcohol  to  the  aqueous  solution  a  distinct  yellowish 
fluorescence  is  produced.     The  addition  of  acid  produces  no  precipitate.     Zinc- 
dust  decolors  the  solution,  but  on  contact  with  air  the  original  color  is  imme- 
diately restored.     The  solution  in  sulphuric  acid  is  green,  and,  on  diluting,  first 
becomes  blue  and  finally  red. — Saffranin  and  Saffranisol  (to  be  distinguished 
from  each  other  by  the  difference  in  tint  of  dyed  specimens). 

3.  The  aqueous  solution  is  a  pure  red  and  shows  a  greenish-yellow  fluores- 
cence, which  becomes  more  distinct  the  more  it  is  diluted.     The  addition  of 
acid  gives  an  orange-yellow  precipitate,  which  is  soluble  in  ether.     The  ethereal 
solution  is  a  pure  yellow,  without  fluorescence.     The  solution  in  sulphuric  acid 
is  yellow. — Eosin  (tetrabromfluorescein). 

4.  The  aqueous  solution  is  more  of  a  bluish-red  and  shows  no  fluorescence. 
Acids  give  a  straw-colored  precipitate,  soluble  in  ether  to  a  liquid  of  the  same 
color.     Concentrated  sulphuric  acid  gives  a  golden-yellow  solution.     Zinc-dust 
decolors  the  ammoniacal  solution.     If  the  colorless  solution  be  dropped  on  blot- 
ting-paper, it  acquires  an  intense  bluish-red  color  by  contact  with  the  air. — 
Eosin- Scarlet,  bromo-nitro-fluorescein,  C2oH8Br2(N02)2O5. 

5.  The  solution  is  bluish-red,  without  fluorescence.     Acids  give  an  orange- 
yellow  precipitate  soluble  in  ether.     Strong  sulphuric  acid  gives  an  orange- 
yellow  solution.     Zinc-dust  and  ammonia  decolor  the  solution,  and  the  color  is 
not  restored  by  contact  with  air. — Phloxin.    Bengal-Red.    (Eosins,  to  be  distin- 


i84  COLORING  MATERIALS. 

guished  from  each  other  by  the  difference  in  tint.     Bengal-red  bears  more  to 
the  blue.) 

6.  The  hot-concentrated  aqueous  solution  solidifies,  on  cooling,  to  a  jelly. 
The  addition  of  acids  causes  a  brown,  flocculent  precipitate.     On  warming' with 
zinc-dust  and  ammonia  the  solution  first  becomes  a  bright  yellow  and  then 
colorless.     Concentrated  sulphuric  acid  dissolves  it  to  a  grass-green  solution. 
On  dilution  the  liquid  first  acquires  a  bluish  tint,  and  then  a  dirty  brown  pre- 
cipitate comes  down. — Biebrich- Scarlet  (Double   Scarlet.     From  amido-azo- 
benzene  sulphonic  acids  with  naphthols). 

7.  Barium  chloride  gives  in  an  aqueous  solution  a  flocculent  red  precipi- 
tate, which,  on  boiling,  suddenly  becomes  crystalline  and  acquires  a  deep 
violet-black  color.     The  solution  is  indigo-blue,  turning  violet  and  red  on  the 
addition  of  water. — Crocein-Scarlet,  3B  (Ber.  d.  chem.  Ges.,  15,  1852) 

8.  The  aqueous  solution  is  colored  a  bright  blue  on  the  addition  of  a  minute 
quantity  of  acid.     Cotton-wool  boiled  in  an  aqueous  solution,  either  with  or 
without  the  addition  of  soap,  is  dyed  a  fast  red.    The  solution  in  sulphuric  acid 
is  slate-colored,  and  this  tint  does  not  change  on  diluting. — Congo-Red. 

9.  The  hot  aqueous  solution  solidifies  on  cooling,  when  there  appears  a  sepa- 
ration of  shining,  bronze-colored  crystals.     The  solution  in  strong  sulphuric 
acid  is  violet,  and  diluting  it  with  water  causes  a  brown  precipitate. — Xylidme- 
ponceau  (Xylidine-red,    from    alpha-naphthol-sulphonic  acid,    D.    P.   26012). 
[Richter's  Organic  Chemistry,  Philadelphia,  1886,,  p.  453.] 

10.  The  concentrated  aqueous  solution,  mixed  with  magnesium  sulphate, 
deposits,  on  cooling,  long,  shining  crystals  of  the  magnesium  salt.    The  solution 
in  sulphuric  acid  is  violet.     Wool  is  dyed  by  it  a  brilliant  scarlet. — Crocein- 
Scarlet,  IB  Extra  (formed  by  the  action  of  diazo-naphthionic  acid  on  crocein- 
beta-naphthol-sulphonic  acid). 

11.  The  aqueous  solution  gives,  with   chloride  of  calcium  or  barium,  an 
amorphous,  flocculent  precipitate.    The  solution  in  concentrated  sulphuric  acid 
is  rose-red  or  carmine,  and  on  diluting  it  a  brownish-red  precipitate  comes 
down. — Coloring  matters  from  beta-naphthol-disulphoiiic  acid,  to  be  distin- 
guished from  each  other  by  the  difference  in  tint  of  dyed  samples:  Ponceau  Rt 
2R,   3R.  Anisol-Red,  coccin.  (D.  R   P.  3229).    [Richter's  Organic  Chemistry, 
Smith's  edition,  p.  469.] 

12.  Wool  is  dyed  magenta-red.     Chloride  of  calcium  gives,  in  an  aqueous 
solution,  a  crystalline  precipitate.    The  solution  in  concentrated  sulphuric  acid 
is  bluish-violet,  becoming  red  on  diluting. — Acid  Azo-ttubin  (D.  R.  P.  26012). 

13.  The  color  of  the  solution  is  a  deep  brownish-red.     Wool  is  dyed  the 
same  color.     The  solution  in  sulphuric  acid  is  blue;  the  addition  of  water  gives 
a  yellowish-brown  precipitate.     The  hot-concentrated  aqueous  solution  gives, 
on  the  addition  of  a  drop  of  saturated  soda  solution,  a  precipitate  of  the  sodium 
salt  in  the  form  of  brown,  pearly  plates. — Roccellin  (Echtrotli).    [Post's  "  Chem. 
Tech.  Anal.,"  p.  983.] 

_  14.  Chlorides  of  calcium  and  of  barium  give  a  flocculent,  amorphous  pre- 
cipitate. The  solution  in  concentrated  sulphuric  acid  is  of  an  indigo-blue. 
—Bordeaux-Blue  (D.  R.  P.  3229).  [Diazonaphthalin-beta-naphtholdisulpho- 
nate.J 

15.  The  aqueous  solution  has  a  fine  bluish-red  color,  which  is  completely 
removed  by  caustic  soda,  and  is  again  restored  by  acetic  acid. — Acid  Magenta 
[sodium  rosaniline  sulphonate]. 

B. — Yellow  and  Orange  Coloring  Matters. 

I.  The  coloring  matter  is  insoluble  in  cold  water,  and  either 
totally  or  very  nearly  insoluble  in  hot  water.  On  the  other 
hand,  it  is  soluble  in  alcohol. 


OF 


WITTS  PLAN  OF  ANALYSIS.  185 

1.  The  solution  is  lemon-colored.    The  color  is  either  unaltered  or  slightly 
deepened  by  the  addition  of  acids  or  alkalies. — Chinophtalon,.     [Cliimaphilin.J 

2.  The  color  of  the  solution  is  golden  yellow.     It  is  unaffected  by  acids. 
It  is  turned  a  deep  brownish-red  by  alkalies  and  by  boracic  acid. — Curcumin 
dye  (Turmeric). 

3.  The  color  of  the  solution  is  golden-yellow.   The  addition  of  hydrochloric 
acid  produces  a  red  color.     Amyl  nitrite  added  to  the  hydrochloric  acid  solution 
produces  no  change  of  color  on  boiling,  nor  is  nitrogen  gas  given  off. — Dime- 
thylamido-azubenzol  (formerly  used  for  coloring  artificial  wax  from  ozokerite). 

4.  Reactions  similar  to  3,    except  that  amyl   nitrite  produces   a  change 
of  color  and  a  small  quantity  of  nitrogen  is  given  off. — Amido-azobenzol, 
C12H9N2.NH2. 

II.  The  coloring  matter  is  soluble  in  boiling  water.     Strong 
sulphuric  acid  dissolves  it  without  anjr  great  change  of  color. 

a. — Caustic  soda  produces  no  precipitate. 
ACID  COLORING  MATTERS. 

1.  The  solution  is  greenish  yellow,  having  a  very  bitter  taste.     Alkalies 
color  it  a  dark  yellow.    Unaffected  by  acids. — Picric  Acid  ( Trinitrophenic  Acid). 

2.  The  solution  is  golden-yellow.     Acids  cause  a  white  precipitate.—  Mar- 
Uus-Yellow  [Naphthalene- Yellow,  C:oH5(NO2)2.ONa+H20]. 

3.  The  solution  is  golden -yellow;  not  precipitated  by  acids.     On  the  addi- 
tion of  chloride  of  potassium  fine,  needle-shaped  crystals  are  precipitated. — 
Acid  NapJithol  Yellow. 

4.  The  solution  is  brownish-yellow,  and  shows  a  magnificent  green  fluores- 
cence, disappearing  on  the  addition  of  hydrochloric  acid,  which  also  gives  a 
precipitate. — Fluorescein  (Uranin),  Benzyl  Fluorescein  (Chrysolin).     These  two 
dyes  can  only  be  distinguished  by  a  careful  examination  of  the  separated  color- 
ing acids.     ["  Watts's  Diet.,"  viii.  1606.    Richter's  Chemistry,  Organic,  Smith's 
edition,  p.  629.] 

5.  The  solution  is  golden-yellow,  and  not  precipitated  by  acids.     It  is  not 
decolored  either  oy  zinc-dust  and  ammonia  or  by  tin-salt  and  hydrochloric  acid. 
— Quinoline-  Yellow. 

1). — Caustic  Soda  gives  a  precipitate. 
BASIC  DYES. 

1.  The  precipitate  with  alkalies  is  yellow  and  is  soluble  in  ether  to  a  bright 
yellow  solution,  with  a  beautiful  green  fluorescence. — Phosphine.     [Chrysani- 
line,  Ci9HnN(NH2)2,  with  a  little  magenta.]    (This  delicate  ether  test  can  also 
be  used  to  detect  phosphine  in  mixtures,  as,  for  example,  with  grenadine,  ma- 
roon, etc.) 

2.  The  precipitate  with  alkalies  is  milk-white ;  soluble  in  ether  to  a  color- 
less solution  with  a  greenish-blue  fluorescence. — Flavanilin,  Ci6Hi4N2. 

3.  The  precipitate  with  alkalies  is  milk-white.    Ethereal  solution  colorless, 
without  fluorescence.     The  yellow  solution,  when  boiled  with  hydrochloric  acid, 
gradually  loses  its  color,  and  finally  becomes  colorless. — Auramin. 

III.  The  coloring  matter  is  soluble  in  water.     The  solution 
in  concentrated  sulphuric  acid  has  a  deep  color. 

Azo-CoLoaiNG  MATTERS. 
a. — Soda  produces  a  precipitate. 


1 86  COLORING  MATERIALS. 

1.  The  color  to  wool  is  yellow.    The  aqueous  solution  solidifies,  on  cooling, 
to  a  bluish-red  jelly.     The  sulphuric  acid  solution  is  brownish-yellow. — Citry- 
soidin  [diamido-azobenzene.    BOCKMANN'S  "Chem.  Tech.  Untersuch.,"  p.  808]. 

2.  The  color  given  to  wool  is  orange-brown.     The  solution  does  not  soli- 
dify on   cooling.      The  solution  in  sulphuric  acid  is  brown. —  Vesuvin  (Bis- 
marck-Brown, Manchester-Brown,  or  Phenylene-Brown).      [Triamido-azoben- 
zene.J 

5. — Soda  does  not  produce  a  precipitate. 

1.  The  solution  in  sulphuric  acid  is  yellow,  becoming  salmon-colored  on 
diluting.     The  aqueous  solution  is  yellow. — Tropceoline- Yellow.1 

2.  The  solution  in  sulphuric  acid  is  yellow,  changing  to  carmine-red  on 
diluting.   The  aqueous  solution  is  yellow,  and  the  substance  crystallizes  out,  on 
cooling,  in  glittering,  golden  scales.    Dilute  acids  produce  a  reddish-violet  pre- 
cipitate.— Methyl-Orange.     Ethyl-Orange. 

3.  The  solution  in  sulphuric  acid  is  violet,  becoming  on  diluting  reddish- 
violet,  and  at  the  same  time  forming  a  steel-gray  precipitate.     The  aqueous  so- 
lution is  yellow,  crystallizing  out  on  cooling.     Calcium  and  barium  chlorides 
give  a  completely  insoluble  precipitate — Tropceolin  00.      Diphenylamine- Yel- 
low.   [SO,CJ2H9N2.NHC6H6.] 

4.  The  solution  in  sulphuric  acid  is  bluish-green,  becoming  violet  on  dilut- 
ing, and  forming  a  steel-blue  precipitate.     The  aqueous  solution  is  yellow;  a 
crystalline  precipitate  separates  from  it  on  cooling.     Barium  chloride  gives  a 
yellow  precipitate,  which  can  be  crystallized  from  a  large  quantity  of  water  in 
shining  plates.— Jaune  N  (Yellow  N).     [BOCKMANN,  p.  310.] 

5.  The  solution  in  sulphuric  acid  is  yellowish-green,  becoming  violet  on 
diluting,  and  forming  a  gray  precipitate.     The  aqueous  solution  is  yellow,  de- 
positing crystals  on  cooling.     Calcium  chloride  gives  an  orange  precipitate, 
which  becomes  red  and  crystalline  on  boiling. — Luteolin.     [C2oHi008.     From 
protocatechuic  acid.] 

6.  The  solution  in  sulphuric  acid  is  carmine,  turning  yellow  on  diluting. 
The  aqueous  solution  is  yellow,  often  cloudy,  and  becoming  a  deep  red  or  violet 
•on  the  addition  of  alcoholic  soda. — Citronin  (Indian- Yellow.     Curcumin.    Pur- 
ree).    [Euxanthin,  Ci9H16Oio.] 

7.  The  sulphuric  acid  solution  is  a  deep  orange.    On  diluting  no  change  of 
color  takes  place.    The  aqueous  solution  is  orange;  on  adding  calcium  chloride 
fine  crystals  of  the  calcium  salt  separate  out. — Orange  O  (D.  R.  P.  No.  3229). 

8.  The  sulphuric  acid  solution  is  a  brown  orange.     No  change  of  color  oc- 
curs on  diluting.     The  aqueous  solution  is  yellow.     A  small  addition  of  hydro- 
chloric acid  causes  a  crystalline  precipitate;  excess  of  hydrochloric  acid  causes 
a  separation  of  the  free  acid  in  gray  needles. — Tropceolin  0  (Chrysoin)  [Resor- 
cin-azo-benzene  sulphonic  acid]. 

9.  The  solution  in  sulphuric  acid  is  carmine-red,  becoming  orange  on  dilut- 
ing.   The  aqueous  solution  is  a  reddish-orange;  chloride  of  calcium  precipitates 
the  fine  red  calcium  salt,  which  crystallizes  from  a  large  proportion  of  boiling 
water  in  needles. — Orange  II.  (Mandarin).     [Tropoeolin  000,  No.  II.] 

10.  The  sulphuric  acid  solution  is  violet,  becoming  orange  on  diluting. 
The  aqueous  solution  is  orange-red,  becoming  carmine  on  the  addition  of  caus- 
tic soda.— Tropceolin  000  [No.  I.]  (Orange  1). 

GREEN  COLORING  MATTERS. 

1.  Soluble  in  water  to  an  olive-brown  solution.    It  easily  dissolves  in  alka- 
lies to  a  grass-green  solution.      Concentrated   sulphuric  acid  dissolves  it  to 

1  On  Tropoeolines  in  general  see  0.  N.  WITT,  1879  :  Jour.   Chem.  Soc., 
35,  179. 


WITT'S  PLAN  OF  ANALYSIS.  187 

a  dirty  brown  solution. — Cdrulein,  C2oH806.     [Post's  "Chem.  Tech.  Anal.," 
p.  991.'] 

2.  Easily  soluble  in  water,  forming  a  bright  green  solution.    Alkalies  give 
it  a  rose-colored  or  gray  precipitate.     Strong  acids  color  it  yellow. —  Victoria- 
Green  [Malackite-Gree ••.     Ci+HisN^CB^.OH.     E.  and  O.  FISCHER,  1878-79: 
Ber.  d.  c/iem.  (Jes.,  n,  2095;  12,  790;  Jour.  Chem.  Soc.,  36,  236.  787]. 

3.  Readily  soluble   in  waier,  forming  a  tine  blue-green  solution.      Acids 
color  it  yellow.     Alkalies  decolor  the  solution  without  producing  any  precipi- 
tate.    A  specimen  of  stuff  dyed  turns  violet  when  heated  above  100°  C. — Iodine 
•and  methyl-green.     [Hexamethyl  rosaniline  compounds.     Bockmann's  "  Chem. 
Tech.  Untersuch,"  p.  298.] 

4.  Easily  soluble  in  water  to  a  correspondingly  pale  green  solution.     Acids 
first  deepen  the  color,  and  then  change  it  to  yellow.     Alkalies  completely  de- 
color the  solution.     Silk  and  wool  can  only  be  dyed  in  an  acid-bath  (distinction 
from  methyl-green,  which  will  dye  in  a  neutral  bath).     Dyed  samples  can  be 
heated  with  safety  for  a  short  time  to  150°  C. — Helvetia-Green.    [Alkali-Green.] 
[Post's    "Chem.    Tech.   Anal.,"  p.   987.      Sodium   sulphonate  of    malachite 
green.] 

BLUE  COLORING  MATTERS. 

1.  Quite  insoluble  in  water,  soluble  in  alcohol  to  blue  solutions  of  various 
shades.     Hydrochloric  noid  at  first  causes  no  change,  but  on  standing  minute, 
sparkling  green  crystals  are  precipitated.     Caustic  soda  produces  a  brownish- 
red  coloration.     Concentrated  sulphuric  acid  dissolves  it,  forming  a  brown  so- 
lution.— Rosaniline- Blue.1    Diphenylamine-Blue.'2    (To  be  distinguished  from 
each  other  by  the  difference  in  tint  of  dyed  silk,  especially  with  an  artificial  light) 

2.  Insoluble  in  water.     The  alcoholic  solution  is  colored  red  by  the  addi- 
tion of  hydrochloric  acid.     Unaltered  by  alkalies.  —Jocloph  nin.     [Derivative 
of  Isatin,  containing  sulphur.] 

3.  Easily  soluble  in  water.     Hydrochloric  acid  gives  a  greenish  precipi- 
tate.    Caustic  soda  gives  a  violet-red  precipitate.     Zinc-dust  reduces  it,  but  the 
color  is  restored  on   contact  with  the  air.     It  contains  zinc. — Mtthylene-Blue 
[Ci6Hi9N3S.     Bockmann's  "  Untersuchungs-Methoden,"  p.  300] 

4.  Tolerably  soluble  in  water.     Acids  color  the  solution  yellowish-brown. 
Alkalies  give  a  red-brown  precipitate. —  Victoria-Blue. 

5.  Readily  soluble  in  water.     The  solution  is  almost  completely  decolored 
by  acids.     Wool  abstracts  the  coloring  matter  from  the  alkaline  solution,  and 
becomes  colored  a  deep  blue  after  washing  with  water  and  treating  with  dilute 
acids. — Alkali-Blue  R,  and  6B. 3    (Distinguished  from  each  other  by  the  dif- 
ference in  tint.) 

6.  Easily  soluble  in  water.     Wool  can  only  be  dyed  in  an  acid-bath.     The 
aqueous  solution  is  not  precipitated  by  alkalies.    Zinc-dust  decolors  permanently. 
—  Water-Blue  (Wasserblau)  R,  6#.4 

1 "  Aniline-Blue:'  "Insoluble  Aniline-Blue."  Spritblau.  Triphenyl- 
rosaniline  hydrochloride.  Insoluble  in  water,  sparingly  soluble  in  alcohol, 
soluble  in  acetic  acid  or  in  aniline  oil.  The  alkali  sulphonates  of  triphenyl- 
rosaniline  constitute  "soluble  blues,"  known  as  "alkali-blue"  and  "water 
blue,"  from  the  name  of  the  solvent  they  require. 

2  Diphenylamine-Blue  is  inferred  to  beatriphenyl-para-rosaniline.   It  forms 
a  sul phonic  acid  soluble  with  alkalies. 

3  "Alkali- Blue"  is  tine  mono  sulphonic  acid  of  triphenyl-rosaniline.     It  is 
not  easily  soluble  in  water  alone,  but  on  adding  alkalies  solution  is  readily  ob- 
tained through  formation  of  a  sulphonate. 

4  "  Water-Blue  "consists  oipoly  sulphonic  acids  of  triphenyl-rosaniline,  with 
(S03H)Q  to  (S03H)4  in  the  molecule.     These  sulphonic  acids  dissolve  in  water 
without  the  help  of  an  alkali. 


1 88  COLORING  MATERIALS. 

7.  Easily  soluble  in  water.     Dyes  only  in  an  acid-bath.    Zinc-dust  and  am- 
monia  form  a  vat;  that  is,  the  color  is  restored  on  contact  with  air.     The  solu- 
tion is  permanently  decolored  by  boiling  with  dilute  nitric  acid. — Indigo-car' 
mine.     [Alkali  salts  of  indigotin-disulphonic  acid,  as  CieHsNaOa  (S03K)2  ] 

8.  Insoluble  in  water,  soluble  in  alcohol.    Alkalies  color  the  alcoholic  solu- 
tion brownish-red  to  violet.     Strong  sulphuric  acid  dissolves  it  to  a  blue  solu- 
tion.— Induline  R,  6B.     [Azo-diphenyl  Blue.]     (The  more  soluble  the  dye  the 
redder  the  color.) 

9.  Soluble  in  water.    Acids  give  a  blue  precipitate.    The  solution  is  colored 
red  to  violet  by  alkalies.    Zinc-dust  and  ammonia  form  a  vat.     Dilute  nitric 
acid  does  not  decolor  the  solution,  even  on  heating. — Indulines  soluble  in  water. 
(Distinguished  from  each  other  by  difference  in  tints.)    [Bockmann's  "  Unter- 
such.,"p.  321.] 

10.  The  commercial  product  is  in  the  form  of  a  gray  paste.     Soda  solution 
gives  a  blue  color  on  exposure  to  che  air. — Leukindophenol, 

11.  The  commercial  substance  is  a  gray  paste,  which  dissolves  in  soda  with- 
out any  blue  coloration.     On  adding  glucose,  and  boiling,  crystals  of  indigo- 
blue  separate  out. — Ortho-nitrophenylpropiolic  Acid. 

VIOLET  COLORING  MATTERS. 

1.  With  difficulty  soluble  in  water;   soluble  in  alcohol.     Sulphuric  acid 
forms  a  cinnamon-colored  solution. — Regina-Purple(Diphenyl-rosaniline). 

2.  Easily  soluble  in  water.    Alkalies  give  a  precipitate.    Hydrochloric  acid 
colors  the  solution  first  green  and  then  yellow. — Methyl  -  Violet,  R,  QB.     Hof- 
mann's  Violet.      (Distinguished   from  each  other  by  the   difference  in  tint.) 
[Methyl- Violet  is  pentamethvl-rosaniline    hydrochloride.     It  is  the  same  as 
"Paris  Violet."     Hofrnann's  Violet  is  triethyl-rosaniline  hydrochloride  or  hy- 
driodide.     For  description  see  Bockmann's  "'Uritersuch.,"  p.  296.] 

3.  Not  readily  soluble  in  water.     Alkalies  give  a  violet  precipitate.     Con- 
centrated sulphuric  acid  dissolves  it  to  a  gray  solution.    On  dilution  the  solution 
becomes  successively  grayish-green,   sky-blue,    bluish-violet,   reddish-violet. — 
Mauvein.     (Perkin's  Violet.     Rosolane.}    [C27H24N4.     By  oxidation  of  aniline 
oil  with  dichromate  and  sulphuric  acid.     Perkin,  1856.] 

4.  Soluble  in  water.     Acids  give  a  blue  precipitate;  alkalies  a  reddish- 
violet  precipitate      With  zinc-dust  and  an  acid,  as  well  as  in  an  ammoniacal 
solution,  it  forms  an  excellent  vat.     The  solution  in  strong  sulphuric  acid  is 
emerald-green,  becoming  sky-blue  on  diluting. — Laufs  Violet  (Thioniii). 

5.  Only  soluble  in  boiling  water.     Hydrochloric  acid  colors  the  solution 
carmine-red.     Sulphuric  acid  dissolves  it  to  a  blue  solution,  becoming  red  on 
diluting. — Oallo-cyanin. 

6  Soluble  in  water  to  a  reddish-violet  solution.  The  addition  of  alcohol 
causes  a  red  fluorescence.  Strong  sulphuric  acid  dissolves  it  to  an  emerald- 
green  solution;  on  diluting  the  color  changes  to  blue  or  violet. — Amethyst, 
Fuchsia,  Oiroflee  (Violet  Saffranin  Dyes).  [Saffranines  are  of  the  type 
Ci8Hi4N"4.  For  a.  brief  description  of  the  group  see  Richter's  Chemistry, 
Organic,  Smith's  ed.,  p.  469;  Bockmann's  "Untersuch.,"  p.  302.] 

Chemical  Determination  of  Red  Dye-  Stuff's,  according  to  Stein.1 

With  fabrics,  a  small  portion,  of  about  one-fourth  inch  square  surface,  is 
treated  in  a  test-tube  with  a  few  c.c.  of  the  reagents  directed.  The  resulting 
color  solutions  are  subjected  to  the  tests, 

I.  The  dye-stuff  is  warmed  with  ammonium  sulphide.  It  turns  more  or 
less  blue  to  greenish. — "Aloes  Dye"  a  mixture  of  Chrysammic  and  Aloetie 
acids  used  upon  wool  and  silk. 

JW.  STEIN,  1870:  Polyt.  Centralbl.^.  616;  Zeitsch.  anal.  Chem.,g,  520. 


STEIN'S  SCHEME.  189 

II.  The  dye-stuff  is  boiled  with  aluminium  sulphate  [filtered,  cooled,  and 
filtered  again,  GOPPELSRODER,  1878]. 

A.  The  solution  turns    red  with  a  golden-green    reflex. — Madder  colors 
(Note  1,  following). 

B.  The  solution  turns  red  without  any  reflex.     On  diluting  it  with  an 
equal  volume  of  sodium  sulphite  solution,  it  is 

(1)  Bleached.    Aniline  reds,  Sandal,  Brazil-wood,  Corallin,  and  Safflower. 

Add  alcohol  to  80  per  cent,  and  boil.     The  solution 
(a)  Colors  decidedly  (a)  bluish-red — Aniline-reds  (Note  2,  p.  191). 

(b)  yellowish-red— Sandal  (Note  3,  p.  191). 
(6)  Does  not  color  at  all,  or  noticeably  (Safflower,  Brazil-wood,  Corallin). 

Warmed  with  lime  solution  it  assumes 

(a)  no  color — Safflower  (Carthamus)  (Note  4,  p.  191), 

(b)  a  red  color  (Brazil-wood   and  Corallin).      Warmed  with  dilute 
sulphuric  acid  it  becomes 

(a)  orange-red — Brazil-wood  (Fernambuc), 

(b)  yellow  and  discolored — Corallin  (Note  5,  p.  191). 

(2)  Not  bleached  (by  the  sulphite).     Archil,  Lac  dye,  Kermes,  Cochineal. 

Add  alcohol  to  80  per  cent,  and  boil.     It  becomes 

(a)  decidedly  red—Archil  (Orseille)  (Note  6,  p.  192), 

(b)  not  red,  or  but  slightly  (Lac,  Kermes,  Cochineal).     It  is  warmed  by 

baryta  solution.     It  takes 

(a)  no  color — Lac  Dye, 

(b)  colors  (Kermes,  Cochineal).      It  is  warmed  with  lime  solution; 

.  colors 

(aa)  brown-red — Kermes  (Coccus  ilicis), 
(bb)  violet — Cochineal^  (Coccus  cacti). 

Note  1,  upon  Stein's  scheme  (above).  The  golden-green 
fluorescence,  after  hot  treatment  with  aluminum  sulphate,  accord- 
ing to  STEIN  and  others,  is  a  distinction  of  natural  madder-red 
from  other  reds,  but  is  wholly  due  to  the  purpurin  of  the  mad- 
der, and  is  not  obtained  with  the  alizarin.  Since  Stein's  report 
artificial  alizarin  has  gradually  supplanted  madder,  and  the  latter 
is  not  now  in  extensive  use.  A  brief  description  of  alizarin  and 
purpurin  is  here  appended. 

Alizarin.  C14H8O4  =  240.  Di-hydroxy-anthraquinone. 
C6H4  :  C202  :  C6H2(OH)2  [OH  :  OH=l":  2~|.  "Madder-Red? 
"Alizarin- Red. " — A  product  of  anthracene,  C^4H10 ,  of  coal-tar, 
from  which  it  is  now  chiefly  obtained,  by  reactions  of  oxidation. 
Before  1869  it  was  wrholly  obtained  from  the  root  of  the  madder 
plant,  Rubia  tinctorum  (Krapp,  in  the  German).  Natural  and 
artificial  alizarin  are  identical  when  each  is  perfectly  purified. 
The  natural  alizarin  comes  from  a  glucoside  of  the  plant,  rube- 
rithric  acid,  C26H28O14.  By  boiling  with  dilute  acids,  also  by  a 
ferment  in  the  madder  root,  two  molecules  of  water  are  taken 
in,  and  a  molecule  of  alizarin  formed,  with  two  of  glucose. — In 
orange-colored  or  yellow  prisms,  or  in  a  brown  paste.  Melting 

'Upon  the  distinction  between  cochineal,  kermes,  and  lac,  three  colors 
alike  in  most  reactions,  see  Stein's  report,  Zeitsch.  anal.  Chem.,  9,  522. 


190  COLORING  MATERIALS. 

point,  282°  C.  (SCHUNCK).  Insoluble  in  cold,  slightly  soluble  in 
boiling  water ;  soluble  in  alcohol,  ether,  methyl  alcohol,  benzene 
(more  readily  on  warming),  or  carbon  disulphide.  Alkalies  and 
alkali  carbonates  dissolve  it  in  water,  the  solution  being  violet  by 
transmitted,  purple  by  reflected  light.  Concentrated  sulphuric 
acid  does  not  decompose  it.  From  the  alkaline  solutions  acids 
precipitate  it  in  reddish  flakes ;  and  alum  precipitates  it  with  a 
red  color.  Alcoholic  solution  of  alizarin,  with  acetate  of  copper 
or  of  iron,  gives  a  purple  precipitate  ;  with  barium  hydrate  solu- 
tion, a  blue  precipitate. 

Sublimation  is  a  serviceable  means  of  examining  alizarin. 
Natural  alizarin  contains  Purpurin,  and  artificial  alizarin  con- 
tains Anthraquinone,  as  impurities.  Alizarin  itself  begins  to 
sublime  at  110°  C.;  the  two  purpuriris  at  160°-170°  C.  (SCHUNCK 
and  ROEMER,  1880).  The  first  sublimate  from  artificial  alizarin, 
at  temperatures  below  140°  C.,  will  contain  crystals  of  anthra- 
quinone  with  the  long  orange  crystals  of  alizarin  (GOPPELSRODER, 
1877-78).  In  natural  alizarin — that  is,  when  anthraquinone,  hy- 
droxyanthraquinone,  and  the  anthraflavic  acids  are  absent — con- 
tinued sublimation  at  1400  C.  removes  the  alizarin,  which  may 
thus  be  estimated  by  the  loss.1 

The  name  alizarine,  in  commerce,  has  been  sometimes  applied 
to  an  extract  of  madder  flowers ;  and  to  Gerancin,  a  product  of 
the  action  of  strong  sulphuric  acid  upon  madder  dye. 

Alizarin-Blue.  C17H19NO4.  Formed  from  Alizarin-Orange 
by  heating  with  sulphuric  acid  and  glycerin.  A  bluish-violet 
paste,  of  about  10$  solid  content.  Soluble  in  alkalies  with 
greenish-blue  color,  an  excess  of  the  alkali  causing  a  precipitate. 
Colored  red-brown  by  sulphuric  or  hydrochloric  acid. 

Alizarin- Orange.  Nitro- Alizarin.  C6H4  :  C2O0  :  C6H 
(NO2)(OH)2  [NO2  :  OH  :  OH  =  1  :  2  :  3].  In  commerce  as  a 
yellow  paste.  Dissolves  in  sodium  carbonate  solution  with  yel- 
low-red ;  in  sodium  hydrate  solution  with  a  red  color;  an  excess 
of  the  caustic  alkali  precipitating  the  solution. 

Purpurin.  C14H8O5  =  256.  Tri-hydroxy-  anthraquinone. 
C6H4  :  C2O2  :  C6H(OH)3  [OH  :  OH  :  OH=1  :  2  :  4].  Can  be 
produced  from  anthracene.  The  isomerides  Isopurpurin  or 
anthrapurpurin,  and  Flavopurpurin  or  "yellow  alizarin,"  have 
a  limited  employment  in  dyeing.  Purpurin  crystallizes  in 
orange-red  needles,  with  one  molecule  of  crystallization-water. 

1  SCHUNCK  and  ROEMER,  1880:  Ber.  d.  client.  Ges.,  13,  41;  Jour.  Chem. 
Soc.,  38,  424.  The  same,  1877:  Jour.  Cliem.  Soc.,  31,  665.  Also,  GOPPELSRO- 
DER, 1877:  Ding,  polyt.  Journ.,  226,  30;  Zeitsch.  anal.  Chem.,  17,  510. 


STAIN'S  SCHEME.  191 

It  is  more  soluble  than  alizarin,  either  in  boiling  water,  al- 
cohol, or  ether.  The  solution  in  alkali  is  red,  in  thin  layers 
purple.  A  dilute  alkaline  solution  soon  bleaches  in  the  air 
and  light.  With  lime  or  baryta,  in  hot  water,  it  forms  a  per- 
fectly insoluble  lake.  Boiling  alum  solution  takes  up  purpurin 
abundantly,  forming  a  yellow-red  solution  of  strong  fluorescence, 
whereby  madder-red  is  distinguished  in  the  scheme  of  Stein 
(p.  188). 

Note  2,  upon  the  scheme  of  STEIN  (p.  189).  Aniline-reds. 
Salts  of  Uosaniline,  C20H19X3=301  (monobasic).  The  hydro- 
chloride  and  acetate,  as  monacid  salts,  constitute  "Magenta," 
"Fuchsin,"  and  "Roseine."  The  nitrate  is  prepared  as  u  Aza- 
leine  "  and  "  Rubiiie."  Rosanilines  are  triamido-toluyl  diphenyl 
methanes,  the  hydrated  base  having  the  structure  (C6H4 .  ^N"H0)2 
(C6H3CH3 .  im2)C .  pH=C20H21]Sr3O.  The  base  forms  monacid 
salts  of  red  color,  triacid  salts  of  a  yellow  color,  and  diacid  salts 
of  little  stability. — Commercial  magenta  or  fuchsin  appears  in 
crystals  of  green  metallic  lustre.  It  is  non-volatile,  decomposing 
at  about  220°  C.  It  has  a  bitter  taste.  Rosaniline  base  is  very 
slightly  soluble  in  water,  but  melts  in  boiling  water.  The  ordi- 
nary salts  of  rosaniline,  the  aniline-reds,  are  soluble  in  hot  water 
and  in  alcohol,  the  solutions  having  a  crimson-red  color,  and 
only  impurities  being  left  in  insoluble  residue.  Addition  of 
acids  changes  the  color  toward  yellow,  with  formation  of  triacid 
rosaniline  salts.  Alkalies  precipitate  free  rosaniline  and  destroy 
the  color  of  the  solution.  Warmed  with  cupric  chloride,  aniline- 
reds  show  a  blue  color.  They  dye  silk  and  wool  a  crimson-red, 
without  a  mordant. — Rosaniline  picrate  forms  fine  red  needles 
nearly  insoluble  in  water.  The  tannate  is  insoluble  in  water,  but 
soluble  in  alcohol,  methyl  alcohol,  or  acetic  acid.  Tannic  acid 
precipitates  rosaniline  from  aqueous  solutions  of  its  ordinary 
salts. 

Note  3.  Sandal-red  is  turned  brown  by  hot  lime  solution  ; 
but  its  red  color  is  intensified  and  finally  changed  toward  blue 
by  hot  diluted  sulphuric,  hydrochloric,  or  acetic  acid. 

Note  4.  8afflower-red  (African  Saffron,  False  Saffron). 
The  action  of  the  lime  solution  is  to  decolor  through  a  change 
to  yellow.  Ammonium  sulphide  decolors  it,  more  readily  by 
addition  of  ammonium  hydrate.  The  red  color  is  restored  by 
acetic  acid. 

Note  5.  Corallin-red.  Peonin.  Prepared  from  Aurin  or 
Rosolic  Acid.  In  violet  powder  or  brown  needles,  soluble  in 
water  as  a  red  solution  having  an  alkaline  reaction.  With  cupric 


192  COLORING  MATERIALS. 

chloride  it  is  decolored  to  gray — a  distinction  from  aniline-red, 
which  is  turned  blue  in  this  test. 

Note  6.  Archil.  Orseille.  Persio.  The  coloring  matter 
derived  from  lichens  of  the  genera  Roccella  and  Leconora.  Vege- 
table acids  in  these  lichens  are  converted  into  orcin,  or  orcinol, 
C6H3(CH3)(OH)2  [1  :  3  :  5],  a  di-hydroxy-toluene.  With  am- 
monia this  gives  rise  to  orcein,  or  "  lichen-red,"  C7H7NO3 ,  the 
chief  constituent  of  archil  dyes.  Litmus  and  Cudbear  also  con- 
tain color  derivatives  of  orcin,  obtained  from  the  lichens.  Orcin 
is  manufactured  from  toluene,  as  a  source  of  orcein,  for  dyeing. 
Orcin  is  colorless  when  pure,  but  becomes  reddish-brown  by  ex- 
posure to  the  air.  Its  crystals,  with  one  molecule  of  water,  melt 
at  58°  C.,  and  becoming  anhydrous  the  mass  distils  at  about 
290°  C.  It  is  soluble  in  boiling  water,  alcohol,  ether,  or  boiling 
benzene.  It  is  capable  of  decomposing  alkali  carbonates  with 
effervescence.  Hypochlorites  give,  with  even  a  trace  of  orcin,  a 
transient,  intense  purple-red  color.  Ammonia,  with  exposure  to 
air,  quickly  converts  orcin  into  orcein,  with  its  deep  purple-red 
co]or. — Orcein  dissolves  sparingly  in  water,  to  which  it  gives  its 
red  color,  dissolves  freely  in  alcohol,  and  freely  in  aqueous  alka- 
lies with  violet-red  tint.  Acids  precipitate  it,  in  part,  from  the 
alkaline  solution,  and  water  precipitates  it  from  the  alcoholic 
solution.  It  is  bleached  by  ammonium  sulphide  ;  also  by  zinc 
added  to  an  ammoniacal  solution  previously  acidulated. 

Reactions  of  Coloring  Materials,  according  to  Fol. 1 
Blues. 

Solution  of  citric  acid  or  dilute  hydrochloric  acid  is  added. 

(a)  Color  changes  to  red  or  orange. — Logwood-Hue. 

(b)  Color  does  not  change. 

Solution  of  calcium  chloride  is  added  to  a  fresh  portion  of  the 
dye-stuff. 

(a)  Color  remains  unchanged. — Prussian  Hue. 

(b)  Color  changes. 

Solution  of  caustic  soda  is  added  to  a  fresh  portion. 

(a)  The  substance  is  decolorized. — Aniline-blue. 

(b)  It  remains  unchanged. — Indigo-Hue. 

Yellows. 

A  portion  is  tested  for  ferric  oxide  by  means  of  potassium 
ferrocyanide  ;  another  part  is  tested  for  picric  acid  by  means  of 

1  F.  FOL,  1874  :  Ding.  pol.  Jour.,  212,  520. 


FOLS  METHOD.  193 

potassium  cyanide  solution.    The  production  of  a  blood-red  color 
indicates  picric  acid. 

If  the  colors  do  not  appear,  another  portion  is  treated  with 
a  boiling  solution  of  1  part  of  soap  in  200  parts  of  water. 

(a)  The  color  changes  to  brown,  but  becomes  yellow  again 

with  an  acid. — Turmeric. 

(b)  The  color  becomes  very  dark. — Rustic.  < 

(c)  The  color  remains  unchanged. —  Weld.    Persian  berries. 

Quercitrin. 
Another  portion  is  boiled  with  stannous  chloride. 

(a)  The  color  remains  unchanged. — Quercitrin. 

(b)  The  color  changes  to  orange.—  Persian  berries. 

If  annatto  is  the  coloring  matter  present,  the  color  changes 
to  greenish-blue  on  boiling  in  concentrated  sulphuric  acid. 

Reds. 

The  substance  is  treated  with  boiling  soap  solution. 

(a)  The  color  is  entirely  discharged. — Saffron-carmine. 

(b)  The  color  is  slightly  discharged. — Aniline-red. 

(c)  The  color  changes  to  yellowish-red  or  yellow. — Brazil- 

wood or  Cochineal.     A  portion  of  the  substance  is 
treated  with  concentrated  sulphuric  acid. 

(1)  A  cherry-red  color  is  produced. — Brazil-wood. 

(2)  A  yellowish-orange  color  is  produced. — Cochineal. 

(d)  The  color  remains  unchanged. — Madder-red.     This  col- 
or is  not  discharged  by  ammonium  chloride,  or  by  a 
mixture  of  equal  parts  of  stannous  chloride,  hydrochlo- 
ric acid,  and  water. 

Greens, 

May  consist  of  blues  and  yellows  in  mixture,  or  of  such  sub- 
stances as  aniline-green. 

The  substance  is  heated  on  the  water-bath  with  alcohol  of  95 
per  cent. 

(I.)  The  alcohol  is  colored  yellow,  while  the  substance  be- 
comes more  and  more  blue. — Indigo  or  Prussian  blue  is  present. 
The  residue  is  washed  and  tested  for  these  blues,  as  already  di- 
rected. The  alcoholic  liquid  is  tested  for  yellows  as  above. 

(II.)  The  alcohol  is  colored  green,  while  the  substance  be- 
comes less  colored. — - Aniline- green  or  a  mixture  of  aniline-blue 
with  yellow  is  present. 

A  part  of  the  substance  is  boiled  with  dilute  hydrochloric 
acid. 


194  COLORING  MATERIALS. 

(a)  The  liquid  is  colored  blue  or  lilac. — Aniline-green  from 

methyl  iodide  is  present. 

(b)  The  substance  is  decolored. — Aniline-green  from  alde- 

hyde. 

(e)  The  substance  is  colored  blue,  while  the  liquid  becomes 
yellow. — Aniline-blue  mixed  with  yellow. 

Violets. 

The  substance  is  boiled  in  calcium  chloride  solution. 

(a)  It  is  unchanged. — Alcanna-violet.1 

(b)  It  is  colored  nankeen-yellow. — Madder-violet. 

(c)  It  is  decolored. — Cochineal-violet. 

Another  portion  is  boiled  in  citric  acid :  the  color  is  lightened. 
— Aniline-violet.  To  distinguish  between  the  two  aniline-violets, 
a  third  part  is  boiled  in  hydrochloric  acid,  which  is  diluted 
with  three  times  its  volume  of  water.  After  washing  it  appears 
blue-violet  if  ordinary  aniline -violet  is  the  color,  while  if  Hof- 
mann's  violet  is  present  the  substance  appears  greenish,  and 
after  washing  light  lilac  or  bluish. 

1  [Alkanet.  The  root  of  Anchusa  tinctoria.  A  red  color,  termed  alkanin, 
or  anchusin.  Used  to  color  pomades  and  oils.  Insoluble  in  cold  water,  soluble 
in  alcohol,  ether,  benzene,  petroleum  benzin,  carbon  disulphide,  fat  oils,  and 
essential  oils,  the  resulting  solutions  having  a  red  color.  The  fixed  alkalies 
dissolve  it  with  a  blue  color,  sometimes  used  to  color  syrups.  On  neutralizing 
the  blue  alkaline  solution,  the  alkanin  is  precipitated,  red  to  brown.  Ammonia 
reacts  with  production  of  alkanna-green.  Alcoholic  solution  of  alkanet  with 
stannous  chloride  gives  a  crimson  precipitate,  with  lead  acetate  a  blue  precipi- 
tate, with  iron  salts  a  violet  precipitate,  and  with  mercuric  chloride  a  flesh- 
colored  precipitate.] 


SOLUBILITIES   OF  ANILINE  DYES. 


195 


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Dissolves 
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Dissolves 
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Dissolves 
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Dissolves 
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Dissolves 
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Dissolves, 
with  violet 
precip. 

Dissolves 
yellow. 

e 

& 

4* 

^ 

£ 

a 

Alizarin. 

Aniline-Blu 
soluble. 

Aniline-Blu 
insoluble. 

Aniline-Brov 
(Havana- 
brown)  . 

Vesuvin-Bro^ 

Aniline-Oran 

Aniline-Rec 

Aniline-Viol 
soluble. 

Aniline-Viol 
insoluble. 

Aniline-Yell 

Chrysamm 
Acid. 

Corallin. 

198  ELEMENTAR  Y  ANAL  YSIS. 

CONCH AIRAMINE,  CONCUSCONINE.  See  CINCHONA 
ALKALOIDS,  p.  92. 

COTTON-SEED  OIL.     See  FATS  AND  OILS. 
CREAM  OF  TARTAR.     See  TARTARIC  ACID. 
CUPREINE.     See  pp.  92  and  153. 
CRYPTOPINE.     See  OPIUM  ALKALOIDS. 
DYES.     See  COLORING  MATERIALS,  p.  181. 
ECGONINE.     See  p.  172. 

ELEMENTARY  ANALYSIS  OF  CARBON  COMPOUNDS.— 
A.  qualitative  analysis  for  the  organic  elements,  C,  H,  and 
N,  is  only  made  for  the  purpose  of  determining  whether  a 
carbon  compound  be  present  or  not,  or  whether  a  given  or- 
ganic compound  be  nitrogenous  or  not.  In  the  case  of  bodies 
not  rapidly  volatile,  (1)  ignition  in  the  open  air,  either  on 
platinum  foil  or  in  a  glass  tube  open  at  both  ends,  will  show 
carbonization  in  case  a  carbon  compound  be  present.  The  fact 
of  carbonization  is  shown  first  by  the  appearance  of  a  black  resi- 
due, and  then  by  its  gradually  burning  away.  In  the  case  of 
volatile  bodies,  or  when  for  any  reason  the  result  of  simply  ignit- 
ing the  body  by  itself  proves  uncertain,  a  resort  is  had  to  (2)  igni- 
tion with  copper  oxide  in  a  small  combustion-tube,  with  tests  of 
the  gas  evolved.  The  dry  substance  is  mixed  with  an  excess  of 
copper  oxide  (previously  ignited  and  cooled),  the  mixture  intro- 
duced into  a  small  tube  of  hard  glass,  the  tube  being  closed  at 
one  end  and  fitted  at  the  other  with  a  tubulated  cork  carrying  a 
small  glass  tube  bent  at  right  angles.  On  applying  heat,  very 
gradually,  to  the  combustion- tube,  the  resulting  gas  is  passed  into 
lime  solution  or  baryta  solution.  If  a  precipitate  be  formed  this 
is  to  be  gathered  in  sufficient  abundance,  and  its  solubility  in 
acetic  acid  with  effervescence  is  tried,  for  the  identification  of 
carbon  dioxide.  Meantime  it  is  observed  whether  there  be  con- 
densation of  liquid  in  the  bent  tube  or  not,  and  droplets  so  ob- 
tained may  be  tested,  with  anhydrous  cupric  sulphate,  for  water, 
as  evidence  of  hydrogen.  But  this  evidence  is  dependent  upon 
the  absence  of  moisture  or  hydrates  in  the  contents  of  the  com- 
bustion-tube. Unless  the  result  of  the  simple  test  just  men- 
tioned be  clearly  conclusive,  it  is  better  to  use  the  safeguards 


ELEMENTARY  ANALYSIS.  199 

against  moisture  directed  for  Quantitative  estimation  of  carbon 
and  hydrogen.  That  is,  the  substance  and  the  copper  oxide  are 
properly  dried  and  secured  from  the  moisture  of  the  air,  and  the 
air  in  the  tilled  combustion- tube  is  replaced  by  dried  air,  before 
the  combustion.  Then  the  combustion  is  conducted  very  slowly, 
and  the  small  conducting  tube  is  kept  cold. — To  be  certain  that 
carbon  dioxide  obtained  by  ignition  does  not  come  from  carbon- 
ates— that  is,  from  non-alkali  carbonates  or  alkali  bicarbonates — 
the  material  is  first  to  be  tested  for  carbonates.  If  these  are 
present,  enough  of  hydrochloric  or  sulphuric  dilute  acid  is  add- 
ed, and  the  material  dried  again. 

If  it  be  found  that  a  carbon  compound  be  present,  to  find 
whether  it  be  a  nitrogenous  compound  or  not,  it  is  sufficient,  in 
the  greater  number  of  cases,  (3)  to  heat  the  dry  substance,  well 
mixed  with  dry  soda-lime,  when  the  nitrogen  is  given  off  in  the 
form  of  ammonia.  The  heating  must  be  to  redness,  and  thorough 
drying  of  the  material,  as  well  as  previous  ignition  of  the  soda- 
lime,  render  the  operation  much  more  convenient.  An  ordinary 
test-tube  may  be  used  for  this  combustion ;  but  a  section  of  com- 
bustion-tubing, of  hard  glass,  with  one  end  closed,  serves  better. 
The  tube  may  be  wrapped  in  a  strip  of  copper  gauze  near  the 
open  end,  and  held  by  the  forceps,  while  the  heat  of  the  flame  is 
very  gradually  applied.  The  test  for  ammonia  is  made  by  moist- 
ened red  litmus-paper,  also  by  the  odor,  and  the  color  given  a 
drop  of  dilute  solution  of  copper  sulphate  held  on  a  loop  of  pla- 
tinum wire.  Bodies  rich  in  nitrogen  give  the  odor  of  singed 
hair  when  merely  burned  in  the  air.  Heating  with  fixed  alka- 
lies does  not  cause  the  production  of  ammonia  from  the  nitrogen 
of  all  organic  bodies.  Some  bodies  so  treated  yield  vaporous 
alkaloidal  compounds,  mostly  showing  the  alkaline  reaction  to 
litmus,  but  not  exhibiting  other  characteristics  of  ammonia. 
Other  bodies,  as  many  of  the  nitro-compounds,  when  treated 
by  combustion  with  fixed  alkali,  give  no  indication  of  the 
presence  of  nitrogen.  For  these  it  is  necessary,  and  for  all  it  is 
sufficient,  to  (4)  heat  the  substance  with  a  fragment  of  metallic 
potassium  for  some  time  (SpicA,  1880),  and  then  test  the  mass 
for  cyanides.  The  fused  mass  is  digested  with  hot  water  and  a 
ferrous  salt,  acidulated,  and  a  drop  or  two  of  ferric  salt  solution 
added.  The  blue  color  of  ferric  ferrocyanide  gives  evidence  of 
nitrogen  in  the  material  taken.  Also  the  test  may  be  made  for 
production  of  sulphocyanate  by  digesting  the  mass  (after  fusing 
with  the  potassium)  with  ammonium  sulphide,  and  then  acidu- 
lating. 

A   qualitative   examination  for  sulphur,  phosphorus,  sele- 


200  ELEMENT  A  RY  ANAL  YSIS. 

nium,  and  arsenic  may  be  made  by  applying  a  strong  oxidizing 
agent,  and  then  testing  for  sulphuric,  phosphoric,  selenic,  and 
arsenic  acids.  The  material  (free  from  the  acids  last  named)  is 
either  digested  with  strong  nitric  acid  (sp.  gr.  1.42)  or  smelted 
.  with  potassium  nitrate,  afterward  treated  with  water,  and  the  ni- 
trate tested  for  the  acids.  For  arsenic  the  material  may  be 
treated,  as  in  the  examination  of  animal  tissues  for  arsenic,  by 
drying,  digesting  with  concentrated  sulphuric  acid  and  repeated 
small  additions  of  nitric  acid  until  the  carbon  compounds  are 
oxidized,  and  the  nitric  acid  then  wholly  expelled,  afterward  neu- 
tralizing with  magnesia,  and  subjecting  the  nitrate  to  Marsh's 
test  for  the  arsenical  mirror.  Arsenic  will  sometimes  be  found 
by  igniting  with  sodium  acetate,  when  cacodyl*  compounds  are 
revealed  by  their  odor.  Phosphorus  may  usually  be  found  by 
heating  the  carbonized  material  with  powdered  magnesium,  inti- 
mately mixed,  in  the  bulb  of  a  reduction-tube,  after  which  phos- 
phorescence appears  in  the  dark. 

For  chlorine,  bromine,  and  iodine,  as  elements  in  an  organic 
compound,  it  is  necessary  to  effect  such  a  decomposition  as  will 
bring  the  chlorine,  etc.,  into  union  as  chlorides,  etc.,  or  into  the 
elementary  form.  Thus  chloral,  chloroform,  and  other  similar 
compounds  do  not  react  with  silver  nitrate  to  form  silver  chlo- 
ride, etc.  The  necessary  liberation  of  the  haloid  elements  is  ob- 
tained in  some  cases  by  digesting  with  strong  potassium  hydrate 
solution,  in  other  cases  by  igniting  in  mixture  with  an  excess  of 
lime  (each  of  known  purity),  after  which  the  aqueous  nitrate  may 
be  acidified  with  dilute  nitric  acid,  and  treated  with  silver  nitrate 
solution  for  precipitates.  See  further  upon  the  quantitative  de- 
termination of  the  halogens. 

To  remove  organic  substances,  in  preparation  for  a  search  for 
inorganic  bodies  in  general,  methods  of  ignition,  use  of  oxidizing 
agents,  application  of  solvents,  and  dialysis  are  described  in  the 
author's  "Qualitative  Chemical  Analysis,"  third  edition,  para- 
graphs 773-778. 

Finally,  in  qualitative  analysis  for  the  elements  in  a  portion 
of  organic  matter,  instead  of  the  direct  examination  for  these 
elements,  above  described,  the  analyst  will  most  often  determine 
at  once  what  organic  compounds  known  in  chemistry ^  he  has  in 
hand,  recognizing  their  likeness  by  their  sensible  qualities,  fixing 
their  identity  by  well-tried  qualitative  reactions,  resorting  to  ap- 
proved means  for  their  separation,  and  proving  their  purity  by 
authorized  tests  for  this  purpose.  A  constant  boiling  point  and 
prescribed  melting  and  congealing  points  are  sought.  The 
qualitative  determination  of  a  known  organic  compound  carries 


ELEMENTARY  ANALYSIS.  201 

with  it  the  evidence  of  the  constituent  elements  of  the  compound. 
Just  as  qualitative  tests  for  ortho-phosphoric  acid,  and  for  its 
purity,  prove  the  presence  of  phosphorus  and  hydrogen  and  oxy- 
gen in  combination  as  H3PO4 ;  so  qualitative  tests  for  benzoic 
acid,  and  for  its  purity,  suffice  to  show  that  only  carbon  and  hy- 
drogen and  oxygen  are  present,  and  that  these  elements  are  united 
as  C6H5CO2H.  The  means  of  separating  organic  compounds, 
and  purifying  them,  have  much  in  common  with  like  means  for 
inorganic  bodies.  Solvents  are  applied,  precipitations  are  made, 
crystallization  is  instituted,  fractional  distillation  is  performed, 
chemical  reactions  are  applied ;  and  these  and  other  means,  as 
given  throughout  this  work,  are  persevered  in  until,  in  all  quali- 
ties, constants  are  reached.  But  when  in  the  course  of  research 
a  new  organic  compound  is  obtained,  and  separated  in  purity,  as 
shown  by  constant  properties,  it  becomes  necessary  to  find  what 
elements  it  contains  and  in  what  proportion  they  stand.  Quali- 
tatively, in  most  cases  it  is  evident  from  the  origin  and  proper- 
ties of  the  new  body  what  elements  it  contains  ;  so  that  the  inves- 
tigator may  proceed  at  once  to  establish  quantitatively,  by  the 
methods  of  organic  combustion  next  to  be  described,  in  what 
proportions  the  elements  are  united,  and  then  what  molecular 
weight  it  has  and  under  what  chemical  formula  it  is  to  find  a 
place  in  science.  Further  upon  the  scope  of  qualitative  and 
quantitative  organic  analysis,  often  termed  "  proximate  organic 
analysis,"  and  to  what  extent  it  depends  upon  elementary  or 
"  ultimate  "  organic  analysis,  see  the  article  upon  OKG-ANIC  ANALY- 
SIS in  this  work. 

ELEMENTARY  ORGANIC  ANALYSIS,  in  the  Quantitative  Deter- 
mination of  the  Elements  of  an  Organic  Compound — often  termed 
"  Ultimate  Organic  Analysis" — rests  upon  the  principles  already 
outlined  for  the  Qualitative  Determination  of  the  Organic  Ele- 
ments. For  the  carbon  and  hydrogen  a  complete  combustion  is 
instituted  in  such  a  way  that  the  combustion-products,  carbon 
dioxide  and  water,  are  obtained  as  measures  of  these  two  funda- 
mental elements.  And  this  simple  application  of  the  chemistry 
of  combustion  has  been  the  means  of  obtaining  the  quantitative 
composition  of  organic  bodies,  from  the  first  establishment  of 
chemical  science  to  the  present  time.1  For  nitrogen,  either  an 

1  LAVOISIER,  1781-1784:  burning  of  the  substance  with  a  measured  volume 
of  oxygen,  and  measurement  of  the  volume  of  carbon  dioxide  produced,  for  cal- 
culation of  weight :  Mem.  A  cad.  Sci.,  1784-87.  BERTHOLLET,  1810:  Mem.de 
I'lnstitut  National,  n,  121.  SAUSSURE,  1807-1814  :  Ann.  CMm.  Phys.,  62, 
225;  78,  57;  89,  273.  GAY-LUSSAC  and  THENARD,  1810-1816:  use  of  chlorate 


202  ELEMENTAR  Y  ANAL  YSIS. 

ignition  with  fixed  alkali  is  made  to  yield  ammonia  for  determi- 
nation, or,  more  often,  combustion  with  its  products  carried  over 
heated  metallic  copper  is  made  to  furnish  free  nitrogen  for 
measurement.  The  oxygen  is  obtained  by  difference.  Methods 
for  direct  estimation  of  the  oxygen  have  been  proposed  from 
time  to  time,  as  briefly  indicated  in  succeeding  pages,  but  none 
of  them  has  come  into  actual  use. 

The  supply  of  oxygen  for  combustion  is  obtained  as  follows : 
(1)  From  copper  oxide.  This  is  either  granular  or  in  powder, 
coarse  or  fine.  It  is  made  by  heating  copper  turnings  or  copper 
scale  with  nitric  acid,  finally  to  ignition,  or  by  igniting  copper 
nitrate  prepared  for  the  purpose.  The  granular  form  is  obtained 
by  incipient  fusion.  Both  granulated  and  coarsely  powdered 
copper  oxide  is  to  be  of  uniform  size,  by  sifting,  free  from  dusty 
oxide.  For  most  uses  in  the  combustion-tubes,  the  granular 
form  moderately  coarse,  or  that  from  the  turnings,  or  the  coarse 
powder  is  to  be  chosen,  in  preference  to  fine  powder.  That  is, 
the  column  is  to  be  sufficiently  permeable  by  gases,  so  that  it 
will  not  be  necessary  to  have  a  channel  over  the  oxide,  in  the 
tube.  To  intermix  with  the  substance  under  analysis  finely  pul- 
verized oxide  is  sometimes  employed,  or  obtained  by  trituration 
of  the  granular  form  during  the  intermixing.  Oxide  of  copper, 
when  heated,  must  evolve  no  nitrous  fumes  nor  carbon  dioxide. 
It  is  hygroscopic  to  a  considerable  extent,  and  in  combustion  for 
carbon  and  hydrogen  it  must  be  absolutely  dry.  For  nitrogen 
determinations  it  is  desirable  to  have  it  dry.  It  may  be  ignited, 
in  a  hessian  crucible,  short  of  incipient  fusion,  and  when  still 
warm  put  up  in  a  flask  with  a  neck  a  very  little  wider  than  the 
combustion-tube,  and  closed  by  a  perforated  stopper  bearing  a 
drying-tube  of  chloride  of  calcium.  Also,  it  may,  with  advan- 
tage, be  dried  by  ignition  in  the  combustion-tube,  in  a  current 
of  dried  air.  This  may  be  done  when  the  oxide  is  to  be  after- 
ward removed  from  the  tube  to  the  flask  in  preparing  the  sub- 
stance for  combustion,  and  it  may  with  still  greater  advantage 
be  done  when  the  substance  is  burned  in  a  boat.  In  use  copper 
oxide  is  reduced  to  cuprous  oxide  or  to  metallic  copper.  With 

as  source  of  oxygen  and  introduction  of  copper  oxide,  also  the  determination  of 
nitrogen:  Ann.  Chim.  Phys.,  74,  47;  Schweiger's  Journal,  16,  16.  DOBEREI- 
NER,  1816:  Schweiger's  Journal,  18,  379.  BERZELIUS,  from  1814:  the  use  of 
horizontal  combustion-tubes  of  glass.  LTEBIG,  1831 :  combustion  with  copper 
oxide,  in  detail  nearly  the  same  as  "  Liebig's  method"  sometimes  employed  at 
present:  Ann.  Phys.  Chem.  Fogg.,  21,  1  (application  to  cinchona  alkaloids). 
BRUNNER,  1838:  oxygen  gas  supplied  for  combustion:  Ann.  Phys.  Chem. 
Pogg.,  44,  138.  BUNSEN:  intermixture  with  copper  oxide  in  the  combustion- 
tube. 


ELEMENT  A  RY  ANAL  YSIS.  203 

the  supply  of  oxygen  gas  at  the  close  of  combustion,  the  reduced 
copper  is  restored  to  oxide.  Otherwise  it  may  be  restored  by 
adding  nitric  acid,  heating,  and  igniting. — (2)  From  lead  chro- 
mate.  This  must  contain  nothing  soluble  in  water,  and  yield  no 
carbon  dioxide  when  heated.  It  fuses  at  a  red  heat.  It  is  pre- 
pared by  melting  in  a  hessian  crucible  and  pouring  out  upon  a 
stone  slab,  when  it  is  pulverized  moderately  line,  sieved,  and 
bottled  for  use.  Or  the  melted  chromate  may  be  poured  into 
water  in  a  copper  vessel,  and  the  granulated  mass  collected, 
dried,  and  pulverized.  It  is  not  hygroscopic.  In  melting  it 
adheres  to  the  combustion-tube.  In  use  it  is  reduced  to  the 
green  chromic  oxide  with  lead  oxide.  To  use  it  a  second 
time  it  is  roasted,  fused,  and  pulverized.  After  the  second  time 
it  requires  oxidation,  by  digesting  the  powder  with  nitric  acid, 
drying,  fusing  again,  and  powdering. — Lead  chromate  is  em- 
ployed instead  of  copper  oxide  when  sulphur,  or  selenium  or 
tellurium,  is  present ;  also,  when  very  difficultly  oxidizable  sub- 
stances are  in  hand.  Its  greater  efficiency  as  an  oxidizing  agent 
lies  chiefly  in  its  being  fusible  during  the  combustion. — MAYER 
(1855)  introduced  into  the  powdered  lead  chromate  one- tenth 
its  weight  of  potassium  dicliromate  previously  fused  and  pul- 
verized. This  mixture  serves  to  expel  from  alkalies  or  alkaline 
earths,  if  these  be  present,  the  carbon  dioxide  they  may  have 
absorbed  from  the  products  of  combustion. — (3)  A  stream  of 
oxygen  gas  is  employed.  This  is  supplied  most  evenly  and  satis- 
factorily from  a  pair  of  gas-holders,  the  one  filled  with  oxygen, 
and  the  other  with  atmospheric  air,  the  stream  from  each  being 
purified  by  passing  through  at  least  two  U -tubes,  one  filled 
with  pumice-stone  and  sulphuric  acid,  to  dry  the  gas,  and  the 
other  filled  with  fragments  of  potassium  hydrate  to  remove 
carbon  dioxide. — Also,  without  a  gas-holder,  a  stream  of  oxy- 
gen is  obtained  by  generating  this  element,  in  the  further  end 
of  the  combustion-tube  itself,  from  lead  dioxide,  heated  in  an 
air-bath  to  180°-200°  C.,  or  by  heating  mercuric  oxide  or  po- 
tassium chlorate  by  the  flame. — Oxygen  is  sometimes  generated 
in  the  combustion- tube  from  chlorate  of  potassium  placed  in  a  pla 
tinum  boat  and  subjected  to  heat. — In  the  preparation  of  oxygen 
for  the  gas-holder,  chlorate  of  potassium,  well  mixed  by  tritura- 
tion  with  one-thousandth  of  its  weight  of  ferric  oxide  (FRESE- 
NIUS),  is  heated  over  the  flame  in  a  plain  glass  retort  not  over 
half  filled.  The  heat  is  applied  very  gradually,  and  as  soon  as 
the  salt  begins  to  fuse  the  retort  is  gently  shaken.  When  the 
air  is  expelled  the  connection  is  made  with  the  gas-holder.  If 
the  proportion  of  ferric  oxide  be  exactly  adhered  to,  the  evolu- 


204  ELEMENT  A  RY  ANAL  YSIS. 

tion  of  gas  will  not  be  impetuous.  100  grams  of  the  chlorate 
will  yield  about  27  liters  of  oxygen.  Oxygen  gas  is  tested  for 
chlorine  by  passing  it  through  silver  nitrate  solution,  and  for 
carbon  dioxide  by  passing  through  lime  solution.  A  splinter  of 
wood  which  has  been  kindled  and  blown  out  should  burst  into  a 
flame  when  introduced  into  a  stream  of  oxygen  gas. 

The  soda-lime  used  as  the  fixed  alkali,  for  the  conversion  of 
organic  nitrogen  into  ammonia  in  the  combustion-tube,1  is  a 
mixture  of  two  parts  of  calcium  hydrate  with  one  part  of  sodium 
hydrate.  It  is  usually  made  by  the  evaporation  of  a  solution  of 
sodium  hydrate  with  the  proportional  quantity  of  slaked  lime. 
S.  W.  JOHNSON  (1872 2)  recommends,  as  more  convenient  and 
even  better,  a  mixture  of  equal  parts  of  crystallized  sodium  car- 
bonate and  slaked  lime,  prepared  by  evaporating  the  mixture.3 
Soda- lime  is  obtained  in  granular  form,  more  convenient  for  the 
greater  part  of  its  uses  than  the  powdered  form. — It  should  not 
evolve  any  trace  of  ammonia  when  heated  with  sugar ;  it 
should  not  be  more  than  slightly  moist ;  and  (unless  prepared 
upon  Johnson's  direction)  should  not  effervesce  very  much  upon 
the  addition  of  acids.  It  is  made  ready  for  use  by  igniting  in  a 
hessian  crucible  at  a  gentle  heat,  and  while  warm  it  is  put  up  in 
a  well-corked  bottle,  or  a  bottle  with  a  tubulated  stopper  carrying 
a  drying  tube  containing  both  calcium  chloride  and  a  little  gran- 
ulated soda-lime. 

Metallic  copper  is  used,  while  heated,  to  reduce  oxides  of 
nitrogen  in  the  combustion-tube,  this  being  necessary,  first,  to 
prevent  error  in  estimating  carbon  by  the  absorption  of  carbon 
dioxide ;  second,  to  avoid  loss  of  nitrogen  in  estimating  this  ele- 
ment by  its  volume  when  free.  Coils  of  copper  gauze  or  foil, 
or  spirals  of  copper  wire,  are  heated  to  redness  in  the  air  long 
enough  to  oxidize  the  surface,  and  then  heated  in  a  stream  of 
hydrogen  to  reduce  the  oxide  formed.  For  the  reduction  the 
coils  are  introduced  into  a  combustion-tube  having  a  tubulated 
stopper  at  each  end,  and  a  current  of  hydrogen  passed  through 

1  VARRENTRAPP  and  WILL,  1841:  Ann.  Chem.  Phar.,  39,  257. 

2  Am.  Chemist,  3,  161;  1879:  Am.  Chem.  Jour.,  i,  77. 

3  '*  Equal  weights  of  sal-soda,  in  clean  (washed)  large  crystals,  and  of  good 
white  and  promptly-slaking  quicklime,  are  separately  so  far  pulverized  as  to  pass 
holes  of  TV  inch,  then  well  mixed  together,  placed  in  an  iron  pot,  which  should 
not  be  more  than  half  filled,  and  gently  heated,  at  first  without  stirring.     The 
lime  soon  begins  to  combine  with  the  crystal  water  of  the  sodium  carbonate, 
the  whole  mass  heats  strongly,  swells  up,  and  in  a  short  time  yields  a  fine  pow- 
der, which  may  be  stirred  to  effect  intimate  mixture  and  to  dry  off  the  excess 
of  water,  so  far  that  the  mass  is  not  perceptibly  moist,  and  yet  short  of  the 
point  at  which  it  rises  in  dust  on  handling.     When  cold  it  is  secured  in  well 
closed  bottles  or  fruit-jars,  and  is  ready  for  use"  (where  last  above  cited). 


ELEMENTARY  ANALYSIS. 


205 


until  the  air  is  expelled,  when  heat  is  applied  as  the  stream  of 
hydrogen  continues.  Coarsely 
granulated  copper  oxide,  reduced 
by  ignition  in  a  current  of  hydro- 
gen, is  employed  to  some  extent 
instead  of  the  spiral  coils,  and  is 
more  efficient  than  they.  All 
copper  reduced  by  ignition  in  a 
stream  of  hydrogen  is  liable  to 
contain  traces  of  occluded  hydro- 
gen, from  which  error  may  arise 
unless  precaution  be  taken.1  At 
ordinary  temperature  it  quickly 
absorbs  moisture  from  the  air. 

Copper  gauze  and  wire  are 
also  used  in  the  combustion-tube 
in  methods  of  combustion  of 
non-nitrogenous  bodies,  requir- 
ing only  to  be  cleaned  by  a  mo- 
mentary ignition  in  the  clear 
flame  before  use. 

Solution  of  Potassium  Hy- 
drate. To  absorb  carbon  dioxide 
in  potash  bulbs,  good  potassium 
hydrate  nearly  free  from  carbo- 
nate is  dissolved  in  an  equal 
weight  of  water.  Some  chemists 
use  a  solution  in  2  parts  of  water ; 
others  a  solution  in  f  part  of 
water.  The  solution  dropped 
into  diluted  mineral  acid  should 
not  effervesce.  It  should  be 
strictly  free  from  nitrite.  It  is 
sometimes  used  a  second  time. 
— Solid  hydrate  of  potassium 
is  also  employed  for  absorption 
in  elementary  organic  analysis, 
taken  either  in  stick  or  in  lump, 
the  drier  the  better. 

Chloride  of  Calcium.  For 
absorption  of  the  water  resulting 
from  combustion,  dried  calcium  chloride  strictly  free  from  alka- 


1  G.  S.  JOHNSON,  1876:  Jour.  Chem.  Soc.,  29,  178. 


206  ELEMENTARY  ANALYSIS. 

line  reaction  is  employed.  In  preparation  the  solution  is  stirred 
while  evaporating,  to  granulate,  and  the  residue  dried  at  about 
200°  C.  It  consists  of  CaCl2.2H2O.  The  granulated  form  is 
much  preferable.  It  may  be  tested,  in  concentrated  solution, 
with  litmus-papers.  It  may  be  prepared  from  crude  fused  cal- 
cium chloride  by  dissolving  in  lime  solution,  filtering,  neutraliz- 
ing with  hydrochloric  acid,  evaporating  to  dryness,  and  heating 
as  above  directed.  But  to  be  well  assured  that  the  calcium  chlo- 
ride is  free  from  uncombined  bases,  the  operator  should  take  the 
precaution  to  pass  dried  carbon  dioxide  through  the  filled  chlo- 
ride of  calcium  tube  for  an  hour  or  two,  and  then  a  current  of 
dried  air  to  restore  the  normal  weight  of  the  tube. — For  drying 
gases  the  crude,  fused  calcium  -chloride,  in  broken  masses,  is 
all  that  is  required.  It  usually  has  an  alkaline  reaction. 

Combustion- tubing  is  to  be  of  hard  potash-glass,  mostly  of 
12  to  14  millimeters  (T\-  to  J  inch)  inner  diameter,  and  about  2 
millimeters  (not  quite  j-  inch)  thickness  of  glass.  It  is  best 
obtained  in  lengths  sufficient  for  two  tubes — that  is,  in  pieces 
mostly  5-J-  to  6J-  feet  long.  For  many  purposes  the  combustion- 
tube  is  drawn  out  at  one  end,  and  preferably  in  bayonet  form,  as 
in  Fig.  9.  A  section  of  tubing  long  enough  for  two  combustion- 


6       H.g.  9          c  cf 

tubes  is  readily  so  drawn  and  bent  that  when  severed  in  the  cen- 
tre the  two  finished  tubes  are  obtained.  The  ed^es  are  to  be 
rounded  in  the  flame.  A  combustion-tube  is  cleaned  with  a 
piece  of  muslin  or  paper  attached  to  a  stiff  wire,  and  is  dried  by 
heating  over  a  flame  or  on  a  water-oven,  while  from  time  to 
time  the  air  is  drawn  out  through  a  small  tube  carried  in  to  the 
closed  end,  when  it  is  well  stoppered. 

Combustion-tubing  of  glass  not  sufficiently  infusible  may  be 
used  by  wrapping  it  with  copper  gauze.  Iron  tubes  are  some- 
times used,  with  special  precautions,  especially  for  nitrogen  de- 
terminations by  ignition  with  the  soda-lime  (CLOEZ,  1863 ;  JOHN- 
SON, 1879).  A  hard-glass  tube  may  be  used  repeatedly  for 
combustion  in  a  stream  of  oxygen  gas,  and  sometimes  more 
than  once  for  combustion  with  admixture  of  the  substance 
with  oxide  of  copper,  not  more  than  once  for  combustion 
with  chromate  of  lead. 

Chloride  of  Calcium  Tubes,  for  the  absorption  of  the  water 
of  combustion  and  for  drying  gases,  are  used  of  various  patterns. 


ELEMENT  A  RY  ANAL  YSIS. 


207 


including  the  one-bulb  and  two-bulb  straight  tube,  and  the  U-tube 
with  and  without  a  bulb :  Fig.  10,  and  in  position  in  Figs.  8  and 
16.  The  tubulated  stoppers  should  be  of  rubber,  or  cork  waxed 
over.  An  empty  bulb  in  the  horizontal  part  of  the  chloride  of 
calcium  tube  has  the  advantage  that  it  serves  as  a  cup  for  a  por- 
tion of  the  water  which 
condenses  in  it,  and  the 
chloride  of  calcium  the 
longer  retains  its  power 
of  absorption. — A  tuft  of 
cotton-wool  is  drawn  into 
the  tube,  so  as  to  rest 
firmly  against  and  within 
the  narrow  part  of  the 
tube  through  which  the 
current  enters,  when  the 
fragments  of  calcium  chloride  are  filled  in,  and  at  the  other  end 
a  cover  of  cotton- wool  or  muslin  is  placed. — Concentrated  Sul- 
phuric Acid  has  been  variously  used,  instead  of  calcium  chloride, 
to  absorb  the  water.1 

Potash  bulbs  are  of  the  two  principal  patterns,  GEISLER'S, 
Fig.  11,  which  are  to  be  preferred,  and  LIEBIG'S,  Fig.  12,  which 
have  long  been  used.  When  in  use  the  larger  bulb  is  placed 
next  the  combustion-tube.  In  being  filled,  the  end  which  is 
nearest  the  combustion — the  one  into  which  the  stream  of  gas  is 


.  11 


to  enter — is  inserted  into  the  solution  of  potassa,  and  a  sufficient 
amount  of  the  liquid  is  drawn  into  the  apparatus.  The  proper 
quantities  of  potash  solution  are  shown  in  the  figures. — Instead 
of  a  bulb  apparatus  for  potash  solution  a  large  bulbed  U-tube, 
illled  with  soda-lime,  is  sometimes  used  as  an  absorbent  of  the 
carbon  dioxide  of  combustion. — A  potash  tube,  either  straight  or 

'DIBBITS,  1876:  Zeitsch.  anal.  Chem.,  15,  122;  MORLEY,  1885:  Am.  Jour. 
Sci.,  [3].  30,  140;  Chem.  News,  54,  33. 


208  ELEMENTARY  ANALYSIS. 

U-form,  filled  with  fragments  of  dry  potassium  hydrate  or  with 
granulated  soda-lime,  is  used  beyond  the  potash  bulbs,  and 
weighed  with  it.  It  guards  against  loss  of  water- vapor  and  of 
traces  of  carbon  dioxide. 

The  Combustion -Furnace  of  ERLENMEYER  is  shown  in  Fig.  8, 
p.  205.  It  requires  a  good  supply  of  gas.  The  combustion- 
furnace  of  G-LASER,  preferable  for  some  combustions,  is  shown  in 
Fig.  16.  In  the  use  of  a  gas  combustion-furnace  the  supply  of 
air  must  be  regulated  with  that  of  gas  to  each  burner.  The 
furnace  should  be  placed  where  it  will  be  secure  against  currents 
of  air  or  the  access  of  acidulous  or  arnmoniacal  gases. 

THE  CONDITIONS  OF  SUCCESS  in  organic  elementary  analysis  are 
attained  by  a  watchful  attention  to  details,  with  a  faithful  study 
of  the  sources  of  error,  throughout  the  operation  and  in  the 
preparation  for  it.  The  sources  of  error  are  so  many  that  even  an 
experienced  operator,  when  commencing  work  with  newly  collect- 
ed appliances,  is  quite  liable  to  failure.  When  the  work  is  well  in 
hand,  and  operations  upon  material  of  known  composition  are 
made  to  succeed  each  other  with  almost  invariable  success,  an 
important  estimation  may  be  undertaken  with  confidence  in  the 
result,  but  this  is  to  be  obtained  as  the  mean  of  several  nearly 
coinciding  determinations. 

ESTIMATION  OF  CARBON  AND  HYDROGEN  IN  BODIES  NOT  CON- 
TAINING NITROGEN. —  Oxygen  supplied  by  Copper  Oxide.  Analy- 
sis of  Solids. — The  substance  to  be  analyzed,  obtained  of  exactly 
constant  composition,  in  respect  to  hydration  and  freedom  from 
all  foreign  matters,  and  (if  pulverizable)  in  very  fine  powder,  is 
introduced  into  a  small  weighing-tube — a  light  cylindrical  con- 
tainer, with  a  caoutchouc  or  fine  cork  stopper,  and  of  3  to  6  c.c. 
capacity.  For  each  elementary  estimation  from  0.3  to  0.4  gram 
is  usually  taken,  and  estimations  may  require  repetition  ;  therefore 
it  is  better  to  take  from  2  to  4  grams  of  the  sample  at  once  in 
the  weighing- tube,  so  that  all  the  desired  estimations  can  be 
made  upon  material  of  constant  composition,  without  danger  of 
loss  or  gain  of  moisture  or  other  constituents.  When  it  is  desired 
closely  to  regulate  the  quantity  of  substance  for  each  combus- 
tion, it  is  well  to  employ  in  addition  a  smaller  weighing-tube  to 
receive  enough  for  one  combustion,  which  is  transferred  from 
the  larger  weighing-tube.  The  management  of  liquids,  soft 
solids,  and  very  volatile  matters  is  given  hereafter  (p.  213). 

The  charging  of  the  combustion- tube,  under  whatever  order 
of  arrangements,  is  to  be  so  effected  that  the  entire  contents  of 
the  tube — including  the  substance  under  analysis,  the  material 


ESTIMA  TION  OF  CARBON  AND  HYDROGEN.     209 

supplying  oxygen,  oxygen  gas,  and  atmospheric  air — shall  be 
strictly  free  from  moisture  before  the  combustion  begins.  To 
remove  moisture  and  exclude  it  from  the  materials  and  the  air 
entering  into  the  combustion-tube,  different  orders  of  operation 
are  adopted  in  different  laboratories  and  directed  by  different 
authorities. 

When  the  substance  is  not  burned  in  a  boat  of  platinum  or 
porcelain,  and  when  the  oxygen  is  supplied  by  copper  oxide,  the 
work  may  be  conducted  as  follows  :  The  filled  potash  bulbs,  dried 
with  filter-paper  at  the  ends  arid  wiped  clean,  with  the  attached 
potash  tube  (if  this  be  employed),  are  weighed,  and  both  openings 
are  afterward  closed  with  sections  of  clean  rubber  tubing  stopped 
with  a  bit  of  glass  rod.  The  chloride  of  calcium  tube  is  weighed, 
and  its  ends  afterward  closed.  The  weighing-tube,  narrow  and 
of  considerable  length,  containing  the  substance  for  analysis,  is 
weighed  without  opening  it.  There  is  provided  granulated  oxide 
of  copper,  which  has  been  taken  after  ignition,  and  while  warm, 
into  a  filling-flask.1  as  described  on  p.  202.  The  dry  combustion- 
tube,  with  its  drawn-out  end  sealed,  is  rinsed  with  some  oxide  of 
copper.  About  four  inches  (10  centimeters)  of  the  body  of  the 
combustion-tube  is  filled  with  the  oxide  of  copper,  taken  from  the 
flask  by  the  mouth  of  the  tube.  The  substance  is  added,  upon 
the  layer  of  copper  oxide,  from  the  weighing-tube,  which  is  in- 
troduced into  the  combustion-tube,  avoiding  the  adhering  of  the 
substance  to  the  inner  surface.  The  weighing-tube  is  closed 
and  put  aside  to  weigh  again.  Another  layer  of  oxide  of  cop- 
per equal  to  the  first  is  taken  into  the  combustion-tube,  add- 
ing at  first  in  such  a  way  as  to  rinse  the  latter.  With  a  stiff 
iron  wire  as  long  as  the  combustion-tube,  bent  in  a  single  cork- 
screw turn  at  one  end  and  in  a  ring  at  the  other  (Fig.  8),  the 
substance  is  well  mixed  with  the  oxide  of  copper,  leaving  undis- 
turbed about  4:  centimeters  (1-J-  inches)  of  the  layer  of  oxide  next 
to  the  bent  end.  Oxide  of  copper  is  added  to  fill  to  within  about 
6  centimeters  (2J-  inches)  of  the  mouth.  A  porous  plug  of  as- 
bestos is  added,  leaving  a  good  free  space,  to  be  kept  clear  of 
condensed  water,  between  the  asbestos  and  the  tubulated  caout- 
chouc stopper.  If  a  cork  stopper  be  used  less  space  is  required. 

Another  method  of  charging  the  tube,  when  copper  oxide  is 
the  sole  source  of  oxygen  for  combustion,  provides  for  mixing 

1  The  copper  oxide  may  be  dried  by  ignition  in  the  tube  with  advantage  in 
this  method  as  in  others.  The  tube  is  filled  with  the  oxide,  then  the  open 
drawn-out  end  is  connected  with  a  set  of  drying-tubes,  and  dried  air  is  either 
sent  by  a  gasometer  or  drawn  by  an  aspirator  through  the  drying-tubes  and  the 
oxide  of  copper,  while  the  latter  is  ignited. 


210  ELEMENTARY  ANALYSIS. 

the  substance  with  some  of  the  oxide  of  copper  in  a  mortar  of 
glass  or  unglazed  porcelain.  The  warmed  mortar  is  placed  on  a 
sheet  of  glazed  paper  on  the  table,  and  the  oxide  of  copper  is 
taken  warm.  Both  the  tube  and  the  mortar  are  rinsed  with 
some  of  the  oxide  of  copper,  and  the  rinsings  put  aside  to  be 
ignited  again.  After  a  layer  of  about  an  inch  (2  centimeters)  of 
the  oxide  of  copper  next  to  the  bayonet-end  of  the  tube,  a  mix- 
ture of  the  substance  with  oxide  of  copper  is  made  by  gentle  tri- 
turation  in  the  mortar,  and  added  in  such  quantity  with  the 
mortar  rinsings  as  will  fill  the  tube  to  or  a  little  beyond  the  mid- 
dle of  its  body.  The  remainder  of  the  tube  is  filled  with  the 
copper  oxide  to  within  about  2J  inches  (or  6  centimeters)  of  the 
mouth,  covering  with  a  porous  plug  of  recently  ignited  asbestos. 

When  the  contents  of  the  tube  are  in  fine  powder  a  channel 
for  the  easy  passage  of  gases  is  made  by  tapping  the  tube  upon 
the  table  as  it  lies  in  horizontal  position.  With  granulated  cop- 
per oxide,  or  that  in  coarse  powder,  a  channel  is  usually  to  be 
avoided. 

The  removal  of  atmospheric  moisture  from  the  filled  com- 
bustion-tube, when  a  gaseous  supply  of  oxygen  is  not  used,  may  be 
accomplished  by  attaching  a  drying-tube  of  chloride  of  calcium, 
and  repeatedly  pumping  out  the  air,  which  is  each  time  permit- 
ted to  flow  back  through  the  drying-tube.  A  small  exhausting- 
syringe  may  be  used,  or  a  filter-pump  acting  through  a  flask 
provided  for  the  admission  of  air  at  will.  But  it  is  a  more  satis- 
factory way  to  pass  a  current  of  dried  air,  drawn  by  an  aspirator 
or  sent  by  a  gasometer,  through  the  tube  from  the  drawn-out 
end,  as  directed  farther  on  to  be  done  for  another  purpose  after 
the  combustion  (p.  212).  When  the  contents  are  dried  the  com- 
bustion-tube is  kept  closed  by  a  caoutchouc  stopper  until  con- 
nected with  the  weighed  chloride  of  calcium  tube  and  potash 
apparatus  for  the  combustion. 

Chr ornate  of  lead  (p.  203)  is  used  instead  of  oxide  of  copper 
for  substances  difficultly  oxidizable,  as  well  as  when  sulphur  is 
present.  In  the  charging  of  the  tube  it  is  used  in  the  same  man- 
ner as  oxide  of  copper.  Having  a  higher  oxidizing  power  than 
copper  oxide,  a  smaller  quantity  is  required,  and  a  narrower  tube 
may  be  used.  The  contents  of  the  tube  should  be  dried  the 
same  as  when  oxide  of  copper  is  used. 

Bichromate  of  Potassium,  with  Oxide  of  Copper,  may  be  used 
as  follows  (GINTL,  1868):  The  combustion- tube  is  charged,  first, 
with  about  2J-  inches  (6  centimeters)  length  of  granulated  copper 
oxide ;  then  with  about  1J  inches  (3  centimeters)  length  of  acid 
cliromate  of  potassium  which  has  been  fused,  pulverized,  and 


ESTIMA  TION  OF  CARBON  AND  HYDROGEN.     211 

kept  dry  ;  then  the  substance  added  from  the  weighing-tube,  and 
again  oxide  of  copper  to  make  about  1J  inches  (3  centimeters). 
With  the  mixing  wire  (p.  205)  the  substance  is  well  mixed, 
leaving  undisturbed  about  half  of  the  layer  of  copper  oxide  next 
the  bayonet-end.  The  tube  is  filled  with  copper  oxide  ;  an  as- 
bestos support  is  placed,  providing  an  open  space  next  the  tubu- 
lated stopper ;  and  the  contents  of  the,  tube  are  deprived  of 
moisture,  as  before  directed. 

In  making  the  combustion  with  oxide  of  copper,  the  com- 
bustion-tube is  placed  in  the  furnace  with  the  end  next  the  chlo- 
ride of  calcium  tube  projecting  as  far  as  the  asbestos  plug.  A 
disc  of  copper  foil  may  be  employed  as  a  shield  over  the  tube  to 
protect  the  stoppered  end  from  too  great  heat.  The  tightness 
of  the  apparatus  can  be  assured  by  expelling  a  little  air,  by  heat- 
ing the  bulb  of  the  potash  apparatus  nearest  the  combustion-tube 
until  a  few  bubbles  of  air  have  escaped,  when  the  liquid  rises  on 
the  side  heated  and  should  then  remain  stationary.  If  the  rubber 
connecting  tubes  are  not  snug  they  are  bound  with  wire.  The 
oxide  of  copper  next  the  chloride  of  calcium  tube  is  heated  first, 
very  gradually,  to  dull  redness,  and  the  heat  is  steadily  carried 
toward  the  substance,  not  rapidly  enough  to  cause  a  tumultuous 
escape  of  expanded  air  through  the  potash  bulbs.  At  the  end 
near  the  mouth  the  combustion-tube  is  maintained  uniformly  at 
a  temperature  high  enough  to  prevent  the  condensation  of  water- 
vapor  within,  but  not  high  enough  to  endanger  melting  the 
tubulated  stopper  if  of  caoutchouc,  or  charring  it  if  of  cork. 
The  column  of  copper  oxide,  back  to  where  the  combustible 
substance  begins  to  be  intermixed,  is  held  at  dull  red  heat,  not 
high  enough  to  endanger  blowing-out  of  the  glass,  while  now  the 
heat  is  carried  very  gradually  back  through  the  substance  itself— 
so  gradually  that  not  more  than  one  or  two  bubbles  a  second  will 
pass  the  liquid  in  the  potash  bulbs.  Certainly  the  bubbling  should 
not  at  any  time  be  too  rapid  to  be  counted.  There  should  not 
be  ernpyreumatic  odor  in  the  escaping  air.  When  the  air  has 
been  nearly  all  expelled,  and  the  gas  which  passes  out  of  the 
chloride  of  calcium  tube  consists  mainly  of  carbon  dioxide,  the 
bubbles  will  pass  through  the  last  potash  bulb  only  at  conside- 
rable intervals,  and  these  intervals  will  be  longer  if  that  portion 
of  unmixed  oxide  of  copper  back  of  the  substance  be  heated,  as 
it  may  be  \n  part  and  with  caution,  before  the  substance  begins 
to  burn.  At  the  end  of  the  operation  all  the  contents  of  the 
tube  are  held  at  full  heat.  As  the  current  of  carbon  dioxide 
ceases  the  liquid  in  the  potash  bulb  next  to  the  combustion-tube 
rises.  Slight  suction  may  now  be  applied  to  the  potash  tube. 


212  ELEMENTARY  ANALYSIS. 

At  this  time,  or  in  anticipation  of  the  time  when  the  combustion 
with  the  copper  oxide  is  completed,  the  heat  is  turned  off  under 
the  rear  end  of  the  combustion-tube  so  that  the  drawn-out  extre- 
mity is  cooled,  and  this  is  then  connected  by  a  rubber  tube  with 
a  set  of  tubes  for  thoroughly  depriving  air  or  oxygen  of  moisture 
and  carbon  dioxide.  Such*  a  set  of  tubes  is  described,  together 
with  the  means  of  supplying  oxygen  and  air,  in  the  directions 
for  combustion  in  a  current  of  oxygen  gas,  following.  The  pot- 
ash tube  is  connected  with  an  aspirator,  either  the  bell  jar  form 
shown  in  Fig.  16,  or  a  bottle  aspirator,  serving  not  only  as  a 
pump  but  as  means  of  regulating  the  flow  of  gases  supplied,  and 
of  preventing  recession  of  the  current. 

To  remove  now  the  carbon  dioxide  and  water-vapor  in  the 
combustion-tube,  and  at  the  same  time  insure  the  absolute  com- 
pletion of  the  combustion,  if  oxygen  gas  has  been  provided,  it  is 
better  to  pass  purified  oxygen  gas  from  the  connection  at  the 
bayonet-end  (Fig.  13)  through  the  combustion-tube  while  it  is 


g 

n 

E 

W 

L         ___i 

UUU  UUUUliUUUUUUUU 


Fig.  13 

heated.  The  connection  is  opened  by  breaking  the  point  of  the 
combustion -tube,  in  the  rubber-tube,  with  a  pair  of  pliers,  and  a 
sufficient  stream  of  oxygen  is  passed.  Now,  as  oxygen  has  a 
higher  specific  gravity  than  air,  the  former  is  to  be  removed  from 
the  absorption-tubes  to  be  weighed,  by  washing  it  out  with  a 
stream  of  purified  air.  This  is  done  by  changing  the  connection 
from  the  oxygen  gasometer  to  an  air  gasometer  (the  position  of 
which  is  shown  in  Fig.  13),  taking  air  through  the  same  tubes 
for  depriving  it  of  carbon  dioxide  and  moisture.  Or,  without  a 
gasometer  for  air,  the  previous  connection  with  the  oxygen  sup- 
ply may  be  opened  for  the  admission  of  air,  purified  as  just 
stated,  and  drawn  through  by  the  aspirator,  long  enough  to  re- 
move the  oxygen.  As  soon  as  the  stream  of  air  is  applied  the 
heat  may  be  diminished,  turning  it  down  very  gradually  to  avoid 
the  breaking  of  the  combustion-tube. —  Without  oxygen  gas,  air 


ESTIMATION  OF  CARBON  AND  HYDROGEN.     213 

dried  and  purified  as  above  directed  may  be  drawn  through  the 
combustion-tube  while  it  is  maintained  at  full  heat,  until  the 
carbon  dioxide  is  removed  from  the  apparatus.  The  combustion 
of  a  substance  mixed  with  copper  oxide  and  with  a  stream  of 
oxygen  throughout  the  operation,  as  sometimes  done,  can  be 
readily  understood  from  the  directions  foregoing,  together  with 
those  given  in  the  following  pages  upon  Combustion  in  a  Pla- 
tinum Boat  with  gaseous  oxygen. — Again,  some  operators,  with 
the  benefit  of  experience,  merely  break  the  point  of  the  com- 
bustion-tube in  the  open  air,  and  draw  through,  by  the  aspirator 
or  by  the  mouth,  sufficient  air  to  displace  the  gaseous  content  of 
-the  apparatus,  as  indicated  by  the  bubbles  no  longer  diminishing 
in  size  as  they  pass  the  potash  bulbs. 

The  chloride  of  calcium  tubes,  and  the  potash  bulbs  with  the 
potash  tube,  are  at  once  closed  with  the  caoutchouc  caps,  and  are 
weighed  without  these  additions. 

With  lead  chromate  the  combustion  is  conducted  so  that  the 
chromate  between  the  substance  and  the  mouth  of  the  tube  is  not 
fused,  but  remains  porous.  The  lead  chromate  intermixed  with 
the  substance  is  not  fused  at  first,  nor  until  the  substance  has  all 
been  heated  ;  but  it  should  be  wholly  fused  at  last,  because  it  is 
a  much  more  powerful  oxidizing  agent  in  the  liquefied  state. 

The  errors  to  be  guarded  against  in  combustion  with  oxide 
of  copper  or  chromate  of  lead  are  those  of  too  high  figures  for 
hydrogen  and  too  low  figures  for  carbon.  With  dry  potash  in 
the  end  tube,  the  use  of  an  aspirator,  and  a  stream  of  dry  air  to 
recover  the  carbon  dioxide  left  in  the  apparatus  at  the  close  of 
the  combustion,  the  loss  of  carbon  may  be  avoided.  To  prevent 
an  excess  "of  hydrogen  requires  vigilance,  its  accomplishment 
lying  mainly  in  the  absolute  removal  of  moisture  before  combus- 
tion. 

It  has  been  stated  1  that  without  the  potash  tube  the  carbon 
averages  about  0.1#  too  low,  while  with  the  potash  tube  it 
averages  near  0.05^  too  high  ;  and  that  [without  the  substitution 
of  dried  air  in  the  filled  combustion-tube]  the  hydrogen  averages 
0.1  to  0.2$  too  high. 

Liquids  are  weighed  and  introduced  into  the  combustion-tube 
in  glass  bulbs.  For  volatile  liquids  these  may  be  made  by  draw- 
ing out  wide  tubing,  Fig.  14,  the  drawn-out  portion  being  about 
5  millimeters  (T\-  inch)  in  external  diameter,  and  in  the  wider 
portion  about  3  centimeters  (1£  inches)  long.  For  either  volatile 
or  non-volatile  liquids  bulbs  of  the  shape  shown  in  Fig.  15 

1  KBKULfi's  "  Organische  Chemie."  1867,  i.  22. 


214  ELEMENT  A  R  Y  ANAL  YSIS. 

may  be  employed.  Bulbs  are  filled  by  passing  through  the  flame 
to  heat  the  air  they  contain,  and  then  immersing  the  open  end 
in  the  liquid,  which  presently  rises  to  fill  part  of  the  tube.  If 
the  liquid  be  volatile,  it  may  now  be  made  to  boil  in  the  tube, 
when,  the  open  end  being  inserted  in  the  liquid,  an  additional 
quantity  is  obtained.  If  an  open  bulb  be  placed  with  its  mouth 
uirler  the  surface  of  a  liquid,  and  the 
whole  put  under  an  air-pump,  on 
drawing  out  the  air  the  liquid  rises 
afterward  in  its  place.  Non- vola- 
tile and  slightly  volatile  liquids  are 
weighed  and  introduced  into  the  com- 
bustion-tube in  'ftpen  bulbs ;  freely 
p.  ,, j  volatile  liquids  are  weighed  in  sealed  ^3^  /J^Fig.15 

bulbs.  In  any  case  the  weight  of  the 
empty  bulb  is  taken  before  filling ;  and  the  capillary  neck  of 
the  bulb  is  drained  as  fully  as  possible  after  filling.  To  seal 
the  mouth  it  is  held  a  moment  in  the  flame,  and  when  cool  it  is 
ready  to  be  weighed. — The  combustion  of  non- volatile  liquids 
and  soft  solids  is  much  better  done  with  a  stream  of  oxygen  gas, 
in  a  platinum  boat.  The  products  of  destructive  distillation  are 
burned  almost  as  fast  as  formed,  the  substance  itself  being  heated 
very  gradually.  On  the  other  hand,  when  freely  volatile  bodies 
are  burned  in  oxygen  gas,  care  is  required,  owing  to  some  liabi- 
lity of  explosion  in  the  combustion- tube.  The  use  of  oxygen 
gas  to  complete  the  combustion  of  the  carbonaceous  residues  of 
volatile  substances  is,  however,  always  desirable.  And  WARREN* 
has  presented  a  method  of  burning  volatile  bodies  with  oxygen 
gas,  by  means  of  a  combustion-tube  packed  with  asbestos,  the 
heat  being  applied  and  the  combustion  effected  only  in  the  an- 
terior end  of  the  tube,  while  the  substance  is  vaporized  in  the 
posterior  end.  A  long  combustion- tube  is  used,  and  the  column 
of  porous  asbestos  packing  acts  like  the  gauze  of  Davy's  safety- 
lamp. — In  filling  the  combustion- tube,  when  liquid  or  volatile 
bodies  are  to  be  burned  with  copper  oxide,  the  coarsely  granular 
oxide  is  taken,  a  layer  of  about  two  inches  of  the  same  is  placed 
at  the  posterior  end,  the  substance  contained  in  two  bulbs  is  in- 
troduced with  some  copper  oxide  between  them,  while  the  com- 
bustion-tube is  upright,  and  the  tube  is  filled  up  with  copper 
oxide.  If  the  bulbs  have  been  sealed,  a  file-mark  is  made  upon 
the  neck,  which  is  broken  as  the  bulbs  are  dropped  into  the  tube. 
Yery  volatile  substances  are  sometimes  introduced  in  small  por- 

'1864:  Chem.  News.    Zeitsch.  anal.  Chem.,  3,  272. 


ESTIMATION  OF  CARBON  AND  HYDROGEN.     215 
tions,  in  several  very  thin  bulbs,  which,  by  holding  a  hot  clay 


shield  near,  are  made  to  burst  in  the  filled  combustion -tube,  either 
while  only  copper  oxide  in  the  front  is  heated,  or  before  heating 


216  ELEMENTAR  Y  ANAL  YSIS. 

at  all.  Less  volatile  liquids,  introduced  in  open  tubes,  may  be 
intermixed  with  the  oxide  of  copper  by  applying  a  single  stroke 
of  the  exhausting  syringe  to  the  tilled  combustion- tube,  causing 
the  liquids  to  boil.  Combustion-tubes  of  good  length  and  width 
are  required,  with  evenly  coarse  granular  copper  oxide  filling 
the  tube  without  a  channel.  Care  is  exercised  to  avoid  explo- 
sions and  the  escape  of  unburned  vapor.  It  is  desirable  to  shield 
the  combustion-tube  under  a  firm  cover  of  copper  gauze. 

Gaseous  bodies  are  subjected  to  the  special  methods  of  Gas 
Analysis  for  elementary  estimations.  These  methods  depend  most- 
ly upon  volume  measures  of  the  gases,  with  measures  of  the  residues 
after  their  absorption,  and  the  products  of  their  combustion.  Such 
a  volume  measure  of  the  residue  after  absorption  is  made  in  the 
chief  method  of  the  analysis  of  solids  for  nitrogen,  as  described 
in  the  pages  following.  In  the  first  elementary  analysis  of  fixed 
bodies,  by  Lavoisier,  the  products  of  the  combustion  were  mea- 
sured in  volume  for  the  calculation  of  weight.  Methods  of  or- 
ganic analysis  for  carbon,  founded  on  gas  measurements,  have 
been  reported  upon  by  SOHULZ  (1866)  and  others.  Gases  may  be 
subjected  to  the  method  employed  for  the  relative  determination 
of  the  carbon  and  nitrogen  of  fixed  substances,  by  volume  mea- 
surement after  combustion,  as  devised  by  Liebig,  Bunsen,  Mar- 
chand,  and  others. 

The  combustion  in  a  platinum  boat,  with  gaseous  oxygen  and 
copper  oxide,  may  be  conducted,  for  a  non-volatile  substance,  as 
follows :  The  furnace  should  have  a  secure,  level,  concave  support 
for  the  combustion-tube.  The  furnace  of  GLASER  (Fig.  16)  has 
gutter-shaped  iron  supports,  which  may  be  placed  together  to 
form  a  continuous  canal.  The  combustion-tube,  of  12  or  14  mil- 
limeters (near  \  inch)  internal  diameter,  and  preferably  4  or  5 
centimeters  (1-J  or  2  inches)  longer  than  the  furnace,  is  open  at 
both  ends,  with  fused  edges  and"  tubulated  rubber  stoppers.  The 
platinum  boat  is  of  size  to  easily  enter  the  tube.  The  oxide  of 
copper,  granulated,  is  taken  cold.  Copper  gauze  and  wire  are 
provided,  the  gauze  in  pieces  about  2  centimeters  (}  inch)  wide, 
rolled  in  plugs  large  enough  to  fit  with  easy  friction  in  the  com- 
bustion-tube, and  cleaned  by  momentary  ignition  in  a  Bunsen 
flame.  One  of  these  plugs  is  pushed  about  25  centimeters  (10 
inches)  into  the  tube ;  from  the  other  end  the  coarsely  granular 
copper  oxide  is  filled  to  within  6  to  8  centimeters  (2  to  3  inches) 
of  the  opening,  settling  it  by  very  slight  tapping,  following 
which  is  inserted  another  plug  of  the  copper  gauze  of  sufficient 
length,  leaving  a  free  space  between  it  and  the  rubber  stopper.1 

1 A  spiral  of  copper  wire  is  used,  forward  of  the  plug,  by  some  chem- 


ESTIMATION  OF  CARBON  AND  HYDROGEN.    217 


A  shield  of  copper  foil  is  put  over  this  end  (Fig.  16).  A  piece 
of  copper  gauze  about  10  centimeters  (or  4  inches)  wide  is  rolled 
about  a  stiff  copper  wire  of  sufficient  length,  doubling  a  bit  of  the 
wire  down  firmly  upon  the  first  turn  of  gauze,  and  rolling  the 
gauze  to  make  a  plug  to  fit  the  tube  easily,  when  the  free  end  of 
the  wire  is  bent,  forming  a  ring  which  will  enter  the  tube,  in 
which  it  is  placed  after  igniting  it  for  a  moment. — The  gasome- 
ters for  oxygen  and  for  air  are  filled,  and  connected  with  an 
apparatus  for  removing  moisture  and  carbon  dioxide.  Each 
gasometer  may  be  connected  wifh  a  separate  bottle  of  potassium 
hydrate  solution,  from  which  both  connections  may  lead  to  a 
single  deep  U-tube  filled  with  coarsely  granular  soda-lime,  and 
then  successively  to  three  deep  U-tubes  filled  with  small  lumps  of 
dry  fused  calcium  chloride.  A  U-tube  containing  pumice-stones 
wet  with  concentrated  sulphuric  acid  may  also  be  interposed  at 
any  point  after  the  soda- 
lime.  See  Fig.  16.  A 
mercury- valve  (Fig.  IT)  ^>  Fig.17 

is  sometimes  interposed 
between  the  coinbustion- 
tube  and  the  purifying 
apparatus  to  prevent  dif- 
fusion of  products  of 
combustion  backward.  A 
good  chloride  of  calcium 
U-tube,  with  bulb  on  the 
horizontal  part  next  the  combustion,  is  filled ;  also  the  Geisler 
potash  bulbs  (Fig.  11)  with  the  potash  tube ;  and  a  bell-jar  as- 
pirator (Fig.  16)  is  provided,  carrying  a  chloride  of  calcium 
tube. 

The  apparatus  being  put  in  place  with  the  combustion-tube 
over  the  furnace,  without  the  platinum  boat,  the  tube  is  heated 
up  throughout,  and  a  slow  current  of  the  dry  air  is  transmitted 
through  the  combustion-tube  alone.  Meanwhile  the  calcium 
chloride  tube  and  the  potash  bulbs  and  tube  are  weighed  with- 
out their  caps,  and  then  closed.  When  the  column  of  copper 
oxide  has  been  heated  for  ten  or  fifteen  minutes  the  heat  is  turned 
down,  the  platinum  boat  is  ignited  and  then  cooled  in  a  desiccator 
and  weighed,  and  from  0.3  to  0.5  gram  of  the  substance  is  trans- 

ists.  All  the  metallic  copper  becomes  coated  with  copper  oxide  during  the  heat- 
ing in  the  stream  of  oxygen  or  air,  and  the  copper  oxide  so  formed  makes  an 
efficient  oxi'dizing  agent  for  the*  gaseous  products  of  incomplete  combustion. 
However  this  anterior  end  of  the  tube  be  filled,  it  is  advisory  to  have  a  free 
space  of  2  or  3  centimeters  (an  inch  or  more)  next  the  caoutchouc  stopper. 


218  ELEMENTAR  Y  ANAL  YSIS. 

0 

ferred  to  the  boat.  The  weight  may  be  taken  in  the  boat,  or,  if 
the  substance  be  affected  in  any  way  by  exposure,  the  substance 
is  added  from  a  stoppered  tube,  weighed  before  and  after  it  is 
taken  (p.  208).  The  air-current  is  stopped  ;  the  chloride  of  cal- 
cium tube  and  the  potash  bulbs  and  tube  are  securely  connected 
by  caoutchouc  tubes  of  clean  inner  surface,  and  the  aspirator  is 
connected  in  place.  The  stopper  at  the  posterior  end  of  the 
combustion-tube  is  taken  out  and  the  copper-gauze  cylinder  with- 
drawn, the  platinum  boat  is  inserted  in  its  place  near  the  short 
copper-gauze  plug,  the  cylinder  and  posterior  stopper  replaced, 
and  the  connections  made  with  the  purifying  apparatus  and 
gasometers.  The  aspirator- valve  is  opened  a  little,  a  few  burners 
nearest  the  chloride  of  calcium  tube  lighted  and  gradually  turned 
up,  and  the  heat  increased  to  dull  redness,  not  sufficient  to  distort 
the  tube,  and  extended  back  to  a  safe  distance  from  the  gauze 
plug— governing  the  aspirator  to  take  out  the  expanded  air.  The 
diminished  gaseous  tension  within  the  apparatus  tightens  the 
connections.  A  difference  of  12  to  15  centimeters  (about  5 
inches)  in  water  level  of  the  bell-jar  aspirator  is  usually  main- 
tained. The  gauze  cylinder  is  now  gently  heated,  and  at  about 
this  point  the  stream  of  air  may  be  exchanged  for  one  of  oxygen, 
running  at  first  not  faster  than  a  bubble  every  two  seconds.  The 
space  next  the  anterior  stopper  is  kept  dry  without  softening  the 
rubber,  and  the  heat  is  brought  back  to  within  4  or  5  centimeters 
(1J  or  2  inches)  of  the  platinum  boat,  when  a  gentle  heat  is 
turned  up  directly  underneath  the  substance.  The  progress  of 
the  combustion  is  observed,  and  the  heat  so  regulated  by  the 
changes  in  the  substance  and  the  bubbling  in  the  potash  bulbs  as 
to  obtain  a  gradual  and  even  progress.  When  the  substance  is 
completely  charred,  and  the  bubbling  through  the  potash  solution 
abates,  the  heat  under  the  boat  is  increased  and  the  How  of  oxygen 
quickened  to  about  one  bubble  per  second.  The  exchange  of  oxy- 
gen for  air  may  be  delayed  till  the  substance  is  charred.  When 
the  carbonaceous  matter  in  the  boat  has  disappeared,  the  heat 
underneath  it  is  lessened  and  the  stream  of  oxygen  quickened ; 
soon  after  which  the  heat  is  partly  turned  down  all  along  the 
tube,  and  the  stream  of  oxygen  exchanged  for  one  of  air.  In  a 
few  minutes  now  the  gasometer  and  aspirator  may  be  shut  off, 
and  the  potash  bulbs  and  tube  and  the  chloride  of  calcium  tube 
at  once  detached,  closed  at  their  openings,  wiped,  and  weighed 
(without  their  caps).  The  platinum  boat  may  be  weighed  for 
estimation  of  ash.  The  combustion-tube  is  cooled  very  gradually, 
and  is  at  once  ready  for  another  combustion,  with  the  same  copper 
oxide,  free  from  moisture.  The  water  in  the  bulb  of  the  chloride 


ESTIMA  TION  OF  CARBON  AND  HYDROGEN.    219 

of  calcium  tube  is  examined  as  to  its  purity,  freedom  from  empy- 
reuma,  etc. 

Liquid  substances  are  weighed  in  bulbs  or  small  tubes,  as 
described  on  p.  213,  placed  upon  the  platinum  boat,  and  subjected 
to  combustion  as  above  directed.  Volatile  substances  are  expelled 
from  the  bulbs  containing  them  before  the  posterior  portion  of 
the  copper  oxide  is  heated,  a  hot  clay  shield  being  held  over  the 
boat  for  that  purpose.  The  relations  of  these  substances  to 
elementary  analysis  have  been  stated  further  on  p.  214. 

ESTIMATION  OF  CARBON  AND  HYDROGEN  IN  NITROGENOUS  COM- 
POUNDS.— The  presence  of  nitrogen  requires  only  such  a  change 
in  the  conditions  of  the  combustion  as  shall  prevent  acidulous 
oxides  of  nitrogen  being  formed  and  carried  into  the  potash 
bulbs  to  increase  their  weight.  This  is  done  by  passing  the 
products  of  combustion  over  metallic  copper  at  red  heat.  The 
preparation  of  copper  for  this  purpose  is  described  on  p.  204. 

In  combustion  of  nitrogenous  compounds  with  copper  oxide, 
as  directed  on  pp.  208,  211,  the  combustion-tube  is  to  be  12  to  15 
centimeters  (about  5  inches)  longer  than  required  for  a  non- 
nitrogenous  body.  A  roll  of  copper  foil  about  12  centimeters 
(near  5  inches)  long  is  prepared  as  directed  on  p.  217,  heated  in 
hydrogen  gas  (p.  204),  and  placed  in  a  drying-oven  at  100°  C. 
The  combustion-tube  is  filled  in  the  ordinary  way,  leaving  room 
for  the  gauze  roll,  which  is  introduced  while  warm  from  the 
drying-oven.  Before  the  mixture  of  substance  and  copper  oxide 
is  heated  in  the  tube  the  metallic  copper  is  brought  to  a  bright 
red  heat,  and  so  maintained  during  the  combustion.  If  gaseous 
oxygen  be  supplied  at  the  close  of  the  operation,  it  is  supplied 
sparingly,  so  as  not  to  oxidize  all  the  metallic  copper  until,  near 
the  close  of  the  combustion,  the  nitrogen  shall  have  been  expelled, 
and  only  carbon  remain  to  be  burned. 

In  combustion  of  nitrogenous  bodies,  for  carbon  and  hydro- 
gen, in  a  stream  of  oxygen  gas,  the  gauze  copper  roll  of  about 
12  cm.  length,  as  above  described,  is  inserted  in  a  space  left  for 
it  in  the  anterior  end  of  the  combustion-tube  (p.  216),  chosen 
longer  on  this  account.  The  copper  oxide  is  first  dried,  in  the 
heated  tube,  in  a  stream  of  dry  air  (p.  202) ;  then  the  air  is  turned 
off,  the  roll  of  metallic  copper  warm  from  the  drying-oven  intro- 
duced into  its  place,  the  platinum  boat  with  the  substance  inserted, 
the  connections  made,  and  the  combustion  commenced.  The 
stream  of  air  is  not  changed  for  one  of  oxygen  until  the  continu- 
ance of  the  combustion  demands  it ;  and  neither  is  used  in  such 
excess  that  the  metallic  copper  becomes  oxidized  before  the  nitro- 


220  ELEMENTAR  Y  ANAL  YSIS. 

gen  has  all  passed  out.  To  burn  out  the  last  traces  of  carbona- 
ceous residue  the  stream  of  oxygen  may  be  used  freely.  The  roll 
of  metallic  copper  is  used  but  once. 

ESTIMATION  OF  NITKOGKEN  IN  CARBON  COMPOUNDS. — Absolute 
determination  by  volume  of  the  gas.  Of  various  serviceable 
methods  for  this  estimation,  the  following  are  here  presented  : 

Method  of  JOHNSON  and  JENKINS/  based  in  good  part  upon 
Dumas's  Method. — The  substance  is  burned  in  mixture  with 
copper  oxide,  and,  by  help  of  oxygen  generated  from  potassium 
chlorate,  put  in  the  rear  of  the  combustion-tube,  the  gaseous  pro- 
ducts being  all  carried  through  a  porous  column  of  heated  metal- 
lic copper  of  length  sufficient  not  only  to  deoxidize  nitrogen 
oxides  but  to  absorb  all  the  excess  of  oxygen.  A  short  layer  of 
heated  copper  oxide,  front  of  the  metallic  copper,  oxidizes  any 
hydrogen  held  occluded  by  the  metallic  copper,  also  traces  of 
carbon  monoxide  formed  by  the  metal.  The  gases  are  received 
in  a  measuring-tube  (azotometer),  over  potash  solution,  which 
they  pass  through,  and  which  absorbs  all  carbon  dioxide,  nitrogen 
being  left  alone  as  a  permanent  gas,  measured  for  quantity. 
Between  the  combustion-tube  and  the  azotometer  is  introduced 
a  mercurial  air-pump,  by  which  the  combustion-tube  is  first  fully 
exhausted  of  air  before  the  combustion,  and  by  which  the  gaseous 
products  left  in  the  tube  after  combustion  are  drawn  out  and 
delivered  to  the  azotometer.8  During  the  combustion  the  gasfc& 
pass  through  the  pump  to  the  azotometer.  After  the  initial  ex- 
haustion of  the  combustion-tube,  carbon  dioxide  is  generated  in  it 
by  heating  a  short  column  of  sodium  bicarbonate  placed  in  the 
very  front  of  tlie  tube,  this  carbon  dioxide,  like  that  formed  in 

1  S.  W.  JOHNSON  and  E.  H.  JENKINS, 4880 :  Am.  Chem.  Jour.,  2,  27;  Zeitsch. 
anal.  Chem.,  21,  274;  Chem.  News,  47,  146.     A  valuable  report  on  Prof.  John- 
son's method  is  given  from  continued  experience  in  its  use,  in  comparison  with 
the  Ruffle  Method,  by  C.  S.  DABNEY,  JR.,  and  B.  VON  HERFF,  1885:  Am.  Chem. 
Jour.,  6,  234.     Also,  valuable  improvements  in  the  pump,  and  a  modification 
of  the  charging  of  the  combustion-tube  by  T.  S.  GLADDING,  1882 :  Am.  Chem. 
Jour.,  4,  42  (illustrated).     The  "'  Official  Methods  of  the  Association  of  Agri- 
cultural Chemists  for  1886-7"  are  given  in  Bulletin  No.  12,  Department  of  Ag- 
riculture, Washington,  1886,  p.  52.     Modifications  of  Dumas's  Method  are  also 
given  by  G.  S.  JOHNSON,   1884:  Chem.  News,  50,  191;  Jour.  Chem.  Soc.,  48, 
189 ;  and  by  ILINSKI  (with  ordinary  laboratory  apparatus),  1884 :  Ber.  d.  chem. 
Ges.,  17,  1347;  Zeitsch.  anal.  Chem.,  24,  76. 

2  DABNEY  (see  last  foot-note)  says :  ' '  For  getting  the  air,  before  combustion, 
and  the  nitrogen  afterward,  out  of  the  tube,  we  have  used  carbon  dioxide  with- 
out a  pump  and  have  obtained  excellent  results.  .  .  .  Magnesite  or  manganese 
carbonate,  put  in  the  back  end  of  the  tube,  are  the  best  sources  for  this  pur- 
pose.    [See,  following,  SIMPSON'S  Method.]    But  more  time  is  consumed  in  this 
way  than  with  a  good,  fast- working,  tight  pump." 


ESTIMA  TION  OF  NITROGEN. 


221 


combustion,  being  taken  up  in  the  azotometer  by  the  potash 
solution. 

The  copper  oxide  is  directed  to  be  made  by  heating  copper 
scale  with  10  per  cent,  of  potassium  chlorate  and  enough  water 
to  make  a  thin  paste,  stirring  till  dry.  and  igniting  until  the  mass 
does  not  glow  when  stirred.  The  potassium  chloride  is  to  be 
washed  out  by  decantation,  and  the  copper  oxide  dried  and  mode- 
rately ignited.  Metallic  copper  is  used  as  fine  copper  gauze  in 
rolls  to  fit  the  combustion-tube,  or  as 
granular  oxide  of  copper  reduced  and 
cooled  in  a  stream  of  hydrogen  (p.  205). 
JPotassium  chlorate  is  prepared  by  fus- 
ing the  commercial  article  in  a  porce- 
lain dish  and  pulverizing  when  cold. 
Sodium  bicarbonate  is  used,  and  must 
be  free  from  organic  matter.  Solution 
of  potass  a  is  made  by  dissolving  com- 
mercial potash  in  sticks  in  less  than  its 
weight  of  water,  and  permitting  the 
excess  to  crystallize  out  when  cold. 
The  same  solution  may  be  used  a  num- 
ber of  times. — The  combustion-tube,  of 
best  hard  glass,  should  be  about  28 
inches  (71  centimeters)  long.  The  rear 
end  is  bent  and  sealed  as  in  Fig.  20. 
It  is  best  to  protect  the  horizontal  part 
with  thin  sheet  copper  or  copper  gauze, 
as  directed  further  on. 

The  azotometer.  Fig.  18,  is  a  modi- 
fication of  SCHIFF'S/  The  gas  is  mea- 
sured in  an  accurately,  calibrated  bu- 
rette, A,  of  120  c.c.  capacity,  graduated 
to  fifths  c.c.,  and  closed  at  the  upper  end  by  a  glass  stop-cock. 
The  lower  end  is  connected,  by  a  perforated  stopper  about  1J 
inches  (4.5  centimeters)  long  and  1J  inches  (3.8  centimeters) 
in  diameter,  with  another  tube,  which  has  two  arms,  one,  D,  to 
receive  the  delivery-tube  from  the  pump,  the  other  to  'connect 
by  a  rubber  tube  with  the  bulb,  F,  of  200  c.c.  capacity,  for  the 
supply  of  potash  solution.  The  burette  is  enclosed  in  a  water- 
jacket  of  about  1}  inches  (4.5  centimeters)  external  diameter. 
Its  lower  end  is  closed  by  the  rubber  stopper  that  connects  the 
burette  with  the  two-armed  tube  below.  The  upper  end  of  the 


1 1868:  Zeitsch.  anal  Chem.,  7,  430.     See  also  ibid.,  1881:  20,  257. 


222 


ELEMENTA RY  ANAL  YSIS. 


H 


jacket  is  closed  by  a  thin  rubber  disk  slit  radially  and  having 
four  perforations :  one  in  the  centre  admitting  the  neck  of  the 
burette,  and  three  others  near  the  circumference.  Through  one 
of  the  latter  a  glass  tube,  L,  bent  as  in  the  fig- 
ure, reaches  to  the  bottom  of  the  jacket,  another 
short  tube  passes  through  the  disk  (these  tubes 
conveying  water  to  and  from  the  jacket),  and 
the  third  hole  supports  the  thermometer.  The 
azotometer  is  held  upright  and  firm  on  a  stand 
by  rings  fitted  with  cork  wedges  around  it. 
The  bulb  for  the  potash  solution  rests  in  a 
slotted  sliding  ring. 

The  air-pump*  used  by  Prof.  Johnson  is  a 
Sprengel  mercury-pump,  modified  so  as  to  be 
easily  constructed  and  durable.  It  is  shown  in 
outline,  with  some  parts  enlarged,  in  Fig.  19. 
Through  a  rubber  stopper  wired  into  the  nozzle 
of  the  mercury  reservoir,  A,  passes  a  glass 
tube,  B,  4  inches  (10.2  centimeters)  long,  and 
this  connects  by  a  stout  rubber  tube,  C,  with 
the  straight  tube,  D,  3  feet  (91.4  centimeters) 
long.  The  stout  rubber  tube,  E,  6  inches  (15.2 
centimeters)  long,  connects  D  with  a  straight 
glass  tube,  F,  of  about  the  same  length  as  D. 
G  is  a  piece  of  combustion  tubing,  1J  inches 
(3.8  centimeters)  long,  closed  below  by  a  doubly 
perforated  soft  rubber  stopper  admitting  the 
tubes  F  and  H,  and  above  by  the  singly  perfo- 
rated rubber  stopper  into  which  the  tube  I  is 
fitted.  The  tube  H  has  a  length  of  45  inches 
(114.3  centimeters).  At  the  bottom  it  is  con- 
nected by  a  fine  black  rubber  tube  (previously 
soaked  in  melted  tallow)  with  a  straight  tube 
of  3  inches  (about  7  centimeters),  and  this  again 
in  the  same  way  with  the  tube  K,  of  7  inches 
(about  18  centimeters)  length.  The  tubes  H 
and  K  should  have  an  internal  diameter  of  1.5  millimeters,  F 
may  be  2  millimeters,  and  D  still  larger.  For  H  and  F  may  be 
used  slender  Bohemian  glass  tubes  of  4  millimeters  external 
diameter.  Their  elasticity  compensates  for  their  slenderness. 
If  heavy  barometer  tubes  be  used  the  stoppers  and  G  must  be 
of  correspondingly  larger  dimensions.  The  joints  at  G  must 

2  A  mercurial  pump  for  nitrogen  is  also  figured  and  described  by  DABNEY, 
1885:  Am.  Chem.  Jour.,  6,  236. 


Kg,  19 


ESTIMA  TION  OF  NITROGEN.  223 

be  made  with  the  greatest  care.  It  is  best  to  insert  the  lower 
stopper  for  half  its  length  into  Gr,  and  F  and  H  should  fit  so 
snugly  as  to  be  inserted  with  effort  when  oiled.  The  tube  I 
must  be  of  stout  glass,  about  a  centimeter  (0.4  inch)  in  diameter, 
and  drawn  at  both  ends  to  a  gradual  taper,  the  outer  end  bent  to 
connect  with  the  combustion- tube,  the  inner  end  when  oiled 
turned  into  a  perforation  of  about  0.5  centimeter  (0.2  inch)  in  the 
upper  stopper.  The  joints  entering  G  are  the  only  ones  having 
to  resist  pressure  into  vacuum,  and  they  must  be  made  with  the 
utmost  care.  If  not  secure  without,  they  are  to  be  trapped  with 
glycerine.  To  do  this  pass  F  and  H  through  a  stopper  of  \  inch 
(or  13  millimeters)  greater  diameter  than  G  and  placed  below  it, 
when,  before  inserting  I,  a  jacket-tube  4  inches  (10  centimeters) 
long  is  fitted  upon  this  stopper,  surrounding  G.  After  I  is  in- 
serted the  trap  is  ready,  to  be  filled  with  concentrated  glycerine, 
which  is  preserved  from  dilution  by  adding  a  stopper  to  the  outer 
tube,  around  I,  split  in  halves  for  adjustment. — The  two  rubber 
tubes  are  both  provided  with  efficient  screw-clamps  to  govern  the 
flow  of  mercury. — The  tubes  D,  F,  H,  and  I  are  secured  by  cork 
clamps  and  wires,  or  otherwise,  to  an  upright  plank,  which  is 
framed  below  into  a  heavy  horizontal  wooden  foot  on  which  rests 
the  mercury-trough.  The  plank  carries  above  a  horizontal  shelf 
for  the  support  of  the  reservoir,  A,  the  neck  of  which  rests  in  a 
perforation  in  the  shelf.  At  the  fastenings  of  the  tubes  upon  the 
upright  support  thick  rubber  tubes  are  interposed  as  elastic  rests. 
The  rubber  tube  joints  should  be  wound  with  waxed  silk.  A 
glass  funnel  is  used  in  A  to  prevent  spattering  of  the  mercury. 

I  I  I  |  :  JO —|  LJ  {  f 

JKCIOs    j    MIXTURE         'RINSINGS!      Cu.      |CuOj  C0a !  ASBESTOS  | 


fi  cm.!        30  cm. 


S  cm. 


; 
12  cm.J5cm.j3cmi   10cm.    I 


'.  20 


The  combustion -tube  is  charged  as  follows :  Of  the  potas- 
sium chlorate  from  3  to  4  grams,  according  to  the  amount  of 
carbon  to  be  burned,  are  placed  in  the  tail  of  the  tube,  Fig.  20, 
followed  by  a  plug  of  ignited  asbestos  just  at  the  bend.  Of  the 
substance  under  analysis  0.6  to  0.8  gram,  from  the  weighing- 
tube,  is  well  mixed  in  a  mortar  (previously  rinsed  with  the 
copper  oxide)  with  dry  (recently  ignited)  oxide  of  copper  enough 
to  fill  11  or  12  inches  (28-30  centimeters)  of  the  tube,  and  the 
mixture  introduced  through  a  funnel.  The  rinsings  of  the  mor- 


224  ELEMENTAR  Y  ANAL  YSIS. 

tar  with  oxide  of  copper  are  added  to  fill  about  3  inches  (Y.6 
centimeters)  of  the  tube,  and  a  second  asbestos  plug  placed.  On 
this  is  placed  the  reduced  copper  for  4  or  5  inches  (10  or  12 
centimeters),  then  a  third  asbestos  plug,  then  2  inches  (5  centi- 
meters) of  the  copper  oxide,  and  a  fourth  plug  of  asbestos,  fol- 
lowed by  0.8  to  1.0  gram  of  the  sodium  bicarbonate.1  The  re- 
maining space  is  loosely  filled  with  asbestos  to  take  the  water  of 
combustion  and  prevent  it  from  flowing  back  upon  the  heated 
glass.  The  anterior  part  of  the  tube  is  wound  with  copper  foil, 
leaving  the  rear  of  the  metallic  copper  visible.  The  filled  com- 
bustion-tube is  placed  in  the  furnace,  on  a  level  with  the  tube, 
I,  of  the  pump  (Fig.  19),  and  carefully  connected  with  the  latter 
by  a  close-fitting  rubber  stopper  moistened  with  glycerine. — The 
azotometer  is  prepared  and  tested  as  follows :  The  bottom  is  fill- 
ed with  mercury  to  about  the  level  indicated  by  the  dotted  line  Gr 
(Fig.  18).  The  arm  D  is  securely  closed  by  a  rubber  stopper.  The 
stop-cock  H  is  greased,  the  plug  inserted,  and  the  cock  left  open. 
The  potash  solution  is  poured  into  F  until  A  is  nearly  full,  and 
some  solution  remains  in  the  bulb  F,  which  is  now  raised  care- 
fully in  one  hand,  while  the  other  hand  is  upon  the  stop-cock  H. 
When  the  solution  has  risen  in  A  very  nearly  to  the  glass  cock, 
the  latter  is  closed,  avoiding  contact  of  the  alkali  with  the 
ground  glass  bearings,  when  the  bulb  is  replaced  in  the  ring  arid 
lowered  as  far  as  may  be.  If  the  level  of  the  solution  in  the 
azotometer  does  not  fall  in  10  or  15  minutes,  it  is  tight. — The 
pump  is  set  in  operation  by  putting  its  delivery-tube  K  in  a 
trough  of  mercury,  supplying  the  reservoir,  A,  with  at  least  500 
c.c.  of  mercury,  and  cautiously  opening  the  clamps  C  and  E. 
If  the  mercury  does  not  start  at  once,  repeatedly  pinch  the  rub- 
ber at  E.  It  should  flow  nearly  as  fast  as  it  can  be  discharged  at 
K,  and  without  filling  the  cylinder  G.  A  complete  exhaustion 

CLADDING  (1882:  Am.  Chem.  Jour.,  4,  45)  dispenses  with  chlorate  of  pot- 
ash, and  puts  about  0.6  gram  bicarbonate  of  soda  in  the  tail  of  the  tube  (1).  The 
space  2  is  filled  with  about  two  inches  of  ignited  asbestos.  The  substance  at  3 
is  mixed  with  copper  oxide,  as  fine  as  sea-sand,  without  dust.  At  space  4  is 
another  0.6  gram  of  the  bicarbonate;  then  is  placed  a  layer  of  copper  shot,  and 
again  a  layer  of  coarsely  granulated  copper  oxide  (6).  The  analysis  is  begun  by 
drawing  the  potash  solution  nearly  to  the  top  of  the  azotometer,  then  turning 
up  lamps  under  6,  and  at  the  same  time  starting  the  pump.  When  a  perfect 
vacuum  has  been  obtained  and  the  copper  oxide  (6)  is  red  hot,  the  lamp  just 
beyond  1  is  turned  up,  and  a  gentle  heat,  just  sufficient  to  drive  off  the  carbon 
dioxide  from, it  and  not  to  heat  space  3,  is  applied.  When  the  tube  is  full  of 
carbon  dioxide  this  lamp  is  turned  off  and  the  tube  again  exhausted.  By  this 
process  of  washing  out  the  tube  several  tenths  of  a  c.c.  of  additional  gas  are 
obtained  and  almost  the  last  traces  of  air  removed.  On  running  the  heat  back 
the  bicarbonate  at  4  gives  off  carbon  dioxide,  and  refills  the  tube  before  the 
combustion  of  the  substance  at  3  begins. 


ESTIMA  TION  OF  NITROGEN.  225 

of  the  combustion-tube  can  generally  be  obtained  in  5  to  10 
minutes'  working  of  the  pump.  If  the  mercury  becomes  ex- 
pended before  the  desired  exhaustion  is  obtained,  the  clamp  C  is 
closed  and  the  mercury  returned  to  A.  Complete  exhaustion  is 
denoted  by  a  clanking  or  rattling  sound  of  the  falling  mercury, 
and  a  half  a  minute  after  this  is  heard  the  clamp  C  may  be  closed. 
If  the  mercury  column  in  H  remains  stationary  for  some  minutes, 
the  connections  are  tight.  The  mercury  trough  is  closed  and 
the  tube  K  placed  in  a  capsule. — Before  connecting  the  azoto- 
meter, heat  is  applied  to  the  part  of  the  combustion-tube  contain- 
ing the  bicarbonate  of  sodium.  Water-vapor  and  carbon  dioxide 
are  evolved,  filling  the  vacuum  in  the  pump  and  displacing  the 
mercury  in  the  tube  H.  The  azotometer  is  placed  at  hand,  its 
bulb  F  is  taken  from  the  ring  and  supported  in  a  box  near  the 
level  of  the  tube  D,  the  stopper  of  which  is  now  removed  with- 
out greatly  changing  the  level  of  the  mercury  (G).  The  tube 
D  is  filled  half  full  or  more  with  water.  As  soon  as  the  mercury 
has  fully  escaped  from  the  pump-tube  K,  this  is  inserted  in  the 
azotorneter-tube  D.  A  few  bubbles  are  allowed  to  escape 
through  the  water,  and  then  the  tube  K  is  passed  down  so  that 
the  gas  escaping  from  the  pump  enters  the  azotometer.  It  will 
facilitate  the  delivery  of  the  gas  if  the  extremity  of  the  pump- 
tube  just  touches  the  inside  of  the  azotometer-tube,  as  near  as 
possible  to  the  surface  of  the  mercury.  The  carbon  dioxide  is 
absorbed  in  passing  through  the  caustic  potash  solution,  and  no 
permanent  gas  should  be  obtained.  In  spite  of  all  precautions 
very  minute  bubbles  of  permanent  gas  will  occasionally  ascend, 
but,  as  will  be  seen  on  observing  the  amount  of  potash  solu- 
tion so  displaced,  the  error  thereby  occasioned  is  extremely 
small. 

In  the  combustion  the  anterior  cupric  oxide  is  first  heated 
to  full  redness,  and  then  the  metallic  copper.  Then  the  com- 
bustion of  the  substance  is  steadily  carried  on,  so  that  the  flow 
of  gas  into  the  azotometer  is  about  one  bubble  a  second,  or  a 
little  faster.  When  the  horizontal  part  of  the  tube  has  all  been 
heated,  and  the  evolution  of  gas  has  nearly  ceased,  the  potas- 
sium chlorate  is  heated  so  as  to  boil  vigorously  with  genera- 
tion of  oxygen.  Any  remaining  carbon  of  the  substance  now 
burns  rapidly,  and  the  reduced  copper  oxide  is  promptly  reox- 
idized.  When  the  layer  of  metallic  copper  in  the  anterior  part 
of  the  tube  begins  to  be  oxidized,  the  generation  of  oxygen  is 
stopped  and  the  heat  lowered  all  along  the  tube,  keeping  the 
metallic  copper  still  at  faint  red  heat.  After  a  few  minutes 
now  the  pump  is  started,  slowly  at  first,  having  some  vessel 


226  ELEMENTARY  ANAL  YSIS. 

under  the  azotometer-tube  D  to  receive  the  mercury.  A  few 
minutes'  pumping  suffices  to  clear  the  tube,  full  exhaustion  be- 
ing indicated  as  stated  on  p.  225.  1 

The  azotometer  is  now  removed  from  the  pump,  the  azoto- 
meter-tube D  is  closed  by  its  rubber  stopper,  the  bulb  (F)  is 
raised  in  its  ring  to  such  a  height  that  the  potash  solution  in 
it  is  nearly  on  a  level  with  that  in  the  burette,  the  iilling-tube 
L  is  connected  with  water-supply,  a  thermometer  is  inserted 
in  the  top  of  the  water-jacket,  and  the  water  allowed  to  run 
until  the  temperature  and  the  volume  of  the  gas  are  constant. 
The  level  of  the  solution  in  the  bulb  is  now  accurately  adjusted 
to  that  in  the  burette,  and  the  temperature  and  the  volume  of 
the  gas  are  read,  as  also  the  height  of  the  barometer.  —  When 
50  per  cent,  potash  solution  is  used  no  correction  for  tension  of 
aqueous  vapor  is  used  by  Prof.  Johnson,  following  the  authority 
of  ScHiFF.3 

The  volume  read  off  is  reduced  to  volume  at  0°  C.  by  divid- 
ing by  1  -f-  (degrees  temperature  C.  observed  X  0.003665).  That 

c.c  of  observed  volume 

is,   -  -TTT^  =•  c.c.  volume  at  0  C. 

'  1  +  (observed  temp.  0.°  X  0.003665) 

The  volume  at  observed  barometric  pressure  is  reduced  to 
volume  at  760  millimeters  barometric  pressure  by  the  (inverse) 
proportion,  760  :  mm.  of  observed  pressure  ::  c.c.  observed 
vol.  :  x  =  c.c.  at  760  mm. 

At  0°  C.,  and  760  mm.  bar.,  1000  c.c.  of  (dry)  nitrogen  weigh 
1.25616  grains. 

The   corrections,   therefore,   may   be  stated  :    mm.   bar.    X 

°f  1  ^  a*  T  temPerature' 


(1  +0.00867  760 
The  value  of  this  fraction  is  given  in  a  table  for  T  0°  to  30°,  by 
J.  T.  BROWN:  Jour.  Chem.  Soc.,  [2],  3,  211;  Watts'  s  Diet. 
Chem.,  vi.  147. 

Correction  for  temperature,  pressure,  and  water-  vapor  tension 
is  made  by  the  formula  : 


1  See  GLADDING,  under  p.  224. 

9  HUGO  SCHIFF,  1868:  Zeitsch.  anal.  Chem.,  7,  432.  This  author  found  in 
several  determinations  that  air  dried  by  passing  through  a  50  per  cent,  potash 
solution,  at  24°  C.,  still  contained  only  108  to  113  milligrams  water  in  19  liters. 
This  would  give  to  nitrogen  a  reading  about  0.007  of  its  volume  too  high.  His 
determinations  of  nitrogen,  by  his  procedure  in  the  absolute  method,  were 
uniformly  a  little  too  low,  thus:  12.9  instead  of  13.2;  31.4  instead  of  31.8:  9.0 
to  9.1  instead  of  9.1;  3.8  to  3.9  instead  of  3.9.  The  deficiency  he  ascribed 
to  retention  of  traces  of  nitrogen  oxides.  And  the  author  advises  to  neglect  the 
correction  for  aqueous  vapor,  in  compensation  for  the  margin  of  loss. 


ESTIMA  TIOX  OF  NITROGEN.  227 

P  =  0.0012562  X  V  X 


0.0036T  T°) 

Wherein  P  =  the  grams  weight  of  the  nitrogen  measured. 
V  =  c.c.  of  observed  volume. 
T°  =  temperature    of    the    azotometer-jacket    in    de- 

grees C. 

B  =  millimeters  of  barometric  reading. 
f   =  tension  of  water-vapor,  at  T°,  found  in   milli- 

meters. 

Of  the  tables  convenient  for  consultation,  to  shorten  calcula- 
tions for  nitrogen,  are  those  of  BATTLE  and  DANCY,  for  use  in 
Analysis  of  Commercial  Fertilizers,  1885  :  North  Carolina  Ex- 
periment Station,  Raleigh,  N.  C.  Also,  for  general  uses,  KOHL- 
MAN  und  FREKICHS,  "  Rechentafeln,"  1882  :  Leipzig. 

The  correction  for  water-vapor  tension  is  purposely  neg- 
lected by  some  chemists,  on  the  ground  (already  mentioned) 
that  strong  potash  solution  leaves  the  gas  nearly  dry.1  On  the 
other  hand,  the  results  by  Johnson's  procedure  in  absolute 
method  for  nitrogen  are  more  apt  to  be  over  than  under  the  true 
quantity  (see  the  citation  from  DABNEY,  under  Ruffle's  Method). 
"When  the  correction  is  required  it  is  made  as  follows  :  Consult 
a  table  of  Tension  of  aqueous  vapor  at  various  temperatures 
(this  tension  being  irrespective  of  pressure),  and  find  the  tension, 
in  height  of  mercury,  for  the  observed  temperature.  Subtract 
this  tension  from  the  barometer  reading  in  the  operation  in 
hand,  as  in  the  formula  above. 

Method  of  Maxwell  Simpson  (1855).  —  Combustion  by  a  mix- 
ture of  copper  oxide  with  mercury  oxide,  the  tube  having  been 
cleaned  of  air  by  a  current  of  carbon  dioxide  liberated  by  heat- 
ing a  carbonate.  The  excess  of  oxygen  is  taken  up  by  a  good 
quantity  of  heated  metallic  copper  in  the  combustion-tube;  the 
carbon  dioxide  by  potash  solution  in  a  receiver  ;  and  the  nitrogen 
is  measured  over  mercury  for  the  calculation  of  its  weight.  The 
mercuric  oxide  is  to  be  prepared  by  precipitation  with  fixed  al- 
kali, washing  with  water  and  then  with  dilute  phosphoric  acid, 
and  drying  at  100°  C.  —  The  combustion-tube,  about  80  centi- 
meters (31.5  inches)  long,  is  closed  in  a  rounded  end  by  fusion. 

1  Owing  to  the  fact  that  the  strength  of  the  potash  solution  varies,  and  the 
water-vapor  tension  is  therefore  uncertain,  GALTERMAN  (1885)  collects  the  ni- 
trogen over  potash  solution  in  a  non-calibrated  tube,  thence  transferring  it  to  a 
measuring-tube  over  distilled  water.  The  full  tension  of  the  water-vapor  is 
deducted. 


228 


ELEMENTARY  ANALYSIS. 


A  mixture  of  12  grams  of  manganese  carbonate  or  of  magnesite, 
previously  dried  at  100°  C.j  with  2  grams  of  the  mercuric  oxide, 
is  introduced  into  the  tube.  A  plug  of  recently  ignited  as- 
bestos is  inserted,  pushing  it  down  to  within  3  centimeters  (about 
1  inch)  of  the  mixture,  and  next  is  added  1  gram  of  the  mer- 
curic oxide.  Of  the  substance  under  analysis  about  0.6  gram  is 
taken,  from  a  weigh  ing- tube,  for  intermixture  in  a  mortar  with 
45  times  its  weight  of  a  prepared  mixture  of  4  parts  of  finely  pow- 
dered and  recently  ignited  copper  oxide,  with  5  parts  of  the  dried 
mercuric  oxide.  The  whole  is  transferred  to  the  combustion- 
tube,  the  mortar  is  rinsed  with  some  more  of  the  mixed  oxides, 
and  the  rinsings  added.  A  second  plug  of  ignited  asbestos  is 
pushed  down  to  within  about  30  centimeters  (near  12  inches)  of 

the  first,  leaving  the  mixture  of 
oxides  loose ;  a  layer  of  6  to  9 
centimeters  (2J-3J  inches)  of 
the  copper  oxide  is  added  and 
a  third  plug  of  asbestos  placed ; 
and  lastly  a  layer  of  as  much  as 
20  centimeters  (near  8  inches) 
of  metallic  copper,  prepared  by 
reducing  granular  copper  oxide 
in  a  stream  of  hydrogen  at  low 
temperature  (or  in  a  stream  of 
carbon  monoxide).  The  com- 
bustion-tube is  now  drawn  out 
and  turned  down,  and  connect- 
ed by  a  section  of  rubber  tubing 

with  a  delivery-tube  adapted  to  reach  beneath  the  surface  of  mer- 
cury in  the  trough.  The  combustion-tube  is  tapped  on  the 
table  to  form  a  channel  for  the  escape  of  the  gases,  and  placed 
in  the  furnace. — A  receiver  is  provided,  as  shown,  with  the 
trough  of  mercury,  in  Fig.  21.  The  receiver  has  about  200  c.c. 
capacity ;  the  glass  stop-cock  should  enable  it  to  hold  mercury 
when  filled  with  it  and  set  up  in  place ;  a  delivery-tube  is  firmly 
connected  with  its  neck,  and  it  is  tubulated  on  the  side  near  its 
base.  This  tubule  carries  an  upright  filling-tube,  with  contrac- 
tion near  the  tubule.  It  is  filled  with  mercury,  placed  in  the 
trough  with  the  tubule  under  the  mercury,  and  about  20  c.c.  of 
strong  solution  of  potassium  hydroxide  passed  into  it.  A  meas- 
uring-tube for  the  nitrogen  gas  is  represented  in  Fig.  22.  But 
instead  of  both  the  receiver  and  measuring-tube  here  described, 
the  azotometer  figured  on  p.  221  may  be  used. 

About  half  of  the  carbonate  in  the  posterior  end  of  the  com- 


ESTIMA  TION  OF  NITROGEN. 


229 


bustion-tube  is  heated,  so  that  the  air  is  driven  out  by  a  current 
of  carbon  dioxide ;  and  at  the  same  time  a  part  of  the  tube  oc- 
cupied by  the  metallic  copper  and  the  copper  oxide  is  heated. 
The  escaping  gas  is  tested  for  air,  from  time  to  time,  by  receiv- 
ing a  few  bubbles  in  an  inverted  test-tube  containing  solution 
of  potash ;  and  when  the  bubbles  are  completely  taken  up  by 
the  solution,  and  the  anterior  part  of  the  tube  is  well  heated, 
the  delivery-tube  from  the  combustion  is  inserted  in  the  lateral 
tubule  of  the  receiver.  The  substance  in  mixture  with  the 
oxides  is  now  gradually  heated,  beginning  next  the  clear  copper 
oxide,  until  the  whole  tube,  except  that  occupied  by  carbonate 
in  the  rear,  has  been  at 
full  heat,  and  no  further 
delivery  of  gas  is  ob- 
served. Next,  the  remain- 
der of  the  carbonate  is 
heated,  so  as  to  sweep 
out  the  nitrogen  remain- 
ing in  the  tube.  The 
delivery-tube  is  now 
withdrawn  from  the  re- 
ceiver, which  is  left  for 
an  hour  for  the  absorp- 
tion of  the  last  traces  of 
carbon  dioxide. 

The  nitrogen  gas  is 
transferred  to  the  measur- 
ing-tube, Fig.  22.  The  stopper  inserted  into  the  lateral  tubule 
of  the  receiver  is  moistened  with  mercuric  chloride  solution  to 
prevent  its  carrying  in  air.  A  drop  of  water  is  placed  in  the 
measuring-tube  before  it  is  filled  with  mercury  and  inverted  in 
the  cistern.  The  stop-cock  in  the  neck  of  the  receiver  is  care- 
fully governed  to  obtain  a  very  gradual  delivery  of  the  gas,  and 
is  closed  each  time  that  the  mercury  is  poured  into  the  filling- 
tube,  below  the  contraction  in  which  the  mercury  is  not  permit- 
ted to  fall  in  the  beginning  of  the  transfer.  Close  the  stop-cock 
as  soon  as  it  is  reached  by  the  potash  solution,  leaving  the  ni 
trogen  in  the  delivery-tube  to  compensate  for  the  air  it  contained 
to  begin  with. 

For  calculation  of  weight  from  volume,  with  corrections  for 
temperature  and  pressure,  see  p.  226. 


A    VERY     SIMPLE     METHOD     FOR     ABSOLUTE     DETERMINATION    OF 

NITROGEN,   when    carefully   conducted,  will   give  good   results. 


230  ELEMENTAR  Y  ANAL  YSIS. 

An  operation  as  follows,  with  copper  oxide  as  the  sole  supply 
of  oxygen,  with  SchifFs  azotometer,  and  without  a  pump,  will 
give  true  results,  though  requiring  more  time  than  the  method 
of  Johnson  or  that  of  Simpson. — The  copper  oxide  is  dried  bj 
ignition  in  a  current  of  dry  air  in  a  combustion-tube  with  bayo- 
net-end. In  a  combustion-tube  of  good  length,  closed  (with 
round  end)  at  the  rear,  a  layer  of  manganese  or  magnesium 
carbonate  is  placed  first,  as  stated  on  p.  228,  then  a  plug  of  as- 
bestos, then  a  short  layer  of  copper  oxide,  then  the  substance 
mixed  with  copper  oxide,  mixing  in  a  mortar  or  in  the  tube. 
About  two-thirds  of  the  tube  should  remain  for  the  layers  of 
copper  oxide  and  metallic  copper.  The  latter  may  be  a  roll  of 
ignited  copper  gauze  or  a  layer  of  reduced  granular  oxide,  and 
should  be  5  to  8  inches  long.  Anterior  to  this  may  be,  as  pro- 
posed by  Professor  Johnson,  a  short  layer  of  copper  oxide  to 
oxidize  any  occluded  hydrogen. 

In  the  combustion  the  air  is  first  expelled  by  liberating  car- 
bon dioxide  from  a  part  of  the  carbonate  in  the  rear ;  the  ante- 
rior layers  of  metallic  copper  and  copper  oxide  are  kept  at  full 
red  heat ;  the  substance  is  burned  very  slowly,  and  much  time 
is  taken  in  oxidizing  the  last  of  the  carbonaceous  residue ;  and 
finally  the  tube  is  swept  out  by  ignition  of  the  remaining  car- 
bonate in  the  posterior  end.  The  gases  from  the  tube  are  re- 
ceived directly  into  a  Schiff's  azotometer,  over  strong  potash 
solution.  In  measuring  the  nitrogen,  the  room  and  apparatus 
being  of  uniform  temperature,  a  thermometric  reading  is  ob- 
tained. 

ESTIMATION  OF  ORGANIC  NITROGEN  BY  ITS  CONVERSION  INTO 
Ammonia.  The  SodctrLime  process  of  Varentrapp  and  Will. — 
The  nitrogen  of  nitrates  is  not  included  in  this  estimation.  The 
substance  is  heated  in  a  combustion-tube  in  mixture  with  soda- 
lime,  the  products  being  carried  through  a  layer  of  red-hot 
soda-linle  of  at  least  half  the  length  of  the  tube,  and  received  in  a 
solution  of  acid.  The  ammonia  remaining  in  the  tube  after  the 
combustion  is  swept  out  by  burning  a  short  layer  of  oxalic  acid 
in  the  rear,  also  by  aspiration.  If  the  substance  be  rich  in  nitro- 
gen it  is  diluted  with  cane-sugar.  The  gaseous  ammonia  from 
the  combustion-tube  is  received  in  a  known  volume  of  a  standard 
solution  of  oxalic  or  sulphuric  acid,  which  is  afterward  titrated 
(PELIGOT'S  modification) ;  or  is  received  in  hydrochloric  acid  for 
gravimetric  estimation  with  platinic  chloride. — Using  Peligot's 
modification,  Prof.  S.  W.  JOHNSON  found1  that,  with  various 

'1879:  Am.  Chem.  Jour.,  i,  75;  1872:  Am.  Chemist,  3,  161. 


ESTIMA  TION  OF  NITROGEN.  231 

substances,  under  a  series  of  determinations,  "  the  soda-iime  pro- 
cess is,  to  say  the  least,  equal  in  accuracy  with  the  absolute 
determination,"  by  volume  of  free  nitrogen.  At  bright  red  heat, 
with  soda-lime,  ammonia  is  not  decomposed. 

A  combustion-tube  of  14  to  30  inches  (35  to  75  centimeters) 
length,  and  near  \  inch  (10  to  12  millimeters)  width,  is  sealed 
round  at  one  end  (Fig.  23).  The  7&?\Qi\mQyQ^&' gas-furnace  is  the 
most  convenient. 
The  best  lulled  U- 
tule  is  that  shown 
in  the  figure.  The 
acid  is  of  about 
normal  strength, 
titrated  with  an 
alkali  solution  of  about  half -normal,  the  latter  being  exactly 
valued  with  a  standard  acid  solution  prepared  with  care.  Prof. 
S.  W.  Johnson  uses  standardized  hydrochloric  acid  and  standard 
solution  of  ammonia,  and  titrates  with  cochineal  tincture  as  an 
indicator.  The  same  indicator  should  be  used  in  all  titrations  ; 
and  if  me  acid  solution  become  colored  from  the  combustion, 
litmus  tincture  is  not  applicable.  Litmus-papers,  blue  and  red, 
serve  vejy  well.  The  soda-lime,  preferably  granulated,  otherwise 
coarsely^ powdered,  is  heated  to  remove  all  moisture,  which  is 
strictly  excluded  until  the  article  is  used.  It  may  be  used  warm 
if  the  sil'bstance  is  stable  enough  to  suffer  no  change  therefrom. 
Oxalic  add  should  be  heated  on  the  water-bath  to  remove  all 
water  of  crystallization.  Asbestos,  recently  ignited,  is  required. 

In  the  charging  of  the  combustion-tube  a  layer  of  about 
1£  inches  (3  centimeters)  of  the  dried  oxalic  acid  is  intro- 
duced into  the  rear  of  the  tube,  followed  by  about  the  same 
length  of  soda-lime.  The  substance  under  analysis  is  added  from 
the  weighing-tube,  in  quantity  about  0.5  gram,  to  some  of  the 
soda-lime  in  a  mortar  (previously  rinsed  with  the  soda-lime),  and 
a  mixture  made  which,  with  the  rinsings  of  the  mortar,  will  fill 
the  tube  to  a  point  from  two-fifths  to  one-half  its  length  from  the 
closed  end.  Or  the  mixture  of  the  substance  with  the  soda-lime 
is  made  in  the  tube  by  means  of  a  stirring-wire  (Fig.  8),  so  as  to 
form  a  layer  of  near  the  length  just  stated.  In  either  case,  if 
the  substance  be  very  rich  in  nitrogen,  about  an  equal  quantity 
of  dried  cane-sugar  may  be  taken  with  it  in  the  mixture.  The 
remainder  of  the  tube  is  filled  with  the  soda-lime  to  within  about 
2  inches  (5  centimeters)  of  the  rubber  stopper,  placing  a  loosely 
porous  plug  of  the  asbestos,  nearly  an  inch  (or  2  centimeters)  in 
length,  as  a  secure  guard  against  the  carrying  forward  of  alkaline 


232  ELEMENTAR  Y  ANAL  YSIS. 

dust  or  spray,  and  leaving  a  free  space  next  the  stopper.  A 
shield  may  be  put  over  the  end  of  the  tube  (Fig.  16).  The 
U-tube  is  filled  and  connected  as  shown  in  Fig.  23.  The 
more  that  moisture  has  been  excluded  from  the  soda-lime,  the 
easier  will  be  the  combustion.  But  the  use  of  warm  soda- 
lime  in  intermixture  with  the  substance  must  not  be  adopted 
without  assurance  that  no  traces  of  ammonia  are  generated  in 
such  mixture.  If  the  soda-lime  be  well  granulated,  or  even 
coarsely  powdered,  with  fine  particles  sifted  out,  it  is  better  not 
to  triturate  in  making  the  mixture  of  the  substance,  and  to  do 
without  a  channel  formed  by  tapping  the  horizontal  tube  on  the 
table,  favoring  the  more  intimate  contact  of  empyreumatic  gases 
with  the  hot  soda-lime.  But  if  there  are  layers  of  line  powder  in 
the  tube,  a  channel  must  be  provided. 

In  the  combustion  the  layer  of  unmixed  soda-lime  is  first 
heated,  beginning  at  the  anterior  end,  and  increasing  and  extend- 
ing the  heat  at  such  a  moderate  rate  that  the  air-bubbles  shall  not 
pass  out  faster  than  about  two  to  each  second.  The  heat  at  the 
anterior  end  is  so  graduated  as  to  prevent  condensation  of  water- 
vapor  in  the  tube,  and  not  to  soften  the  rubber  stopper.  When 
the  mixture  of  substance  is  reached  the  layer  of  clear  soda-lime 
must  be  at  full  red  heat,  and  so  preserved  while  the  flames  are 
advanced  backward  more  gradually  than  before,  delivering  only 
about  one  bubble  every  second.  The  carbonized  substance  is  at 
last  burned  out  with  a  full  red  heat,  and  when  the  delivery  of 
gas  has  nearly  or  quite  ceased  the  oxalic  acid  is  very  gradually 
heated,  so  that  the  carbon  dioxide  shall  not  be  tumultuously 
evolved.  The  carbon  dioxide  is  generated  only  long  enough  to 
sweep  out  the  combustion-tube,  when  the  U-tube  may  be  de- 
tached. The  acid  liquid  should  be  as  little  colored  and  empy- 
reumatic as  possible.  The  anterior  end  of  the  combustion-tube, 
in  the  space  in  front  of  the  asbestos  plug,  should  not  change 
moistened  red  litmus-paper. 

In  titrating  the  acid  for  the  amount  of  ammonia  it  has  re- 
ceived, the  volumetric  alkali  is  added  from  the  burette  directly 
to  the  U-tube  until  the  neutral  point  is  very  nearly  obtained, 
with  litmus-papers  or  other  indicator,  not  phenol-phthalein. 
The  acid  is  now  transferred  to  a  beaker,  with '  very  little 
rinsing-water,  and  the  titration  completed.  The  value  of  the 
alkali  solution  is  found  by  a  volumetric  acid  of  absolute  stand- 
ard. 17  :  14  ::  quantity  of  ammonia  :  x  =  quantity  of  nitrogen. 

Combustion-tubes  with  the  posterior  end  drawn  out  are  some- 
times used,  and  the  residual  ammonia  obtained  by  aspiration,  or 
by  sending  through  a  current  of  carbon  dioxide. 


ESTIMATION  OF  NITROGEN.  235 

The  gravimetric  determination  of  the  ammonia,  as  ammo- 
nium platinic  chloride,  is  done  by  the  ordinary  method,  as  found 
in  works  on  inorganic  analysis,  washing  the  precipitate  with  alco- 
hol or  ether- alcohol,  and  igniting  in  a  weighed  crucible.  194.4 
parts  of  Pt  represent  14  parts  of  N". 

Combustion  with  soda-lime  in  an  iron  tube  may  be  done  with 
good  results,1  as  the  writer  has  verified.  The  tube  should  be 
about  a  third  longer,  and  a  little  wider,  than  a  glass  tube  for  the 
same  combustion.  Special  precaution  is  necessary  to  avoid  burn- 
ing or  melting  the  stoppers. 

Combustion  with  soda-lime,  sulphur,  and  thiosulphate. 
RUFFLE'S  METHOD,  1881.  Reduction  by  a  powerful  deoxidizer 
in  presence  of  a  strong  alkali.  Obtains  the  nitrogen  of  organic, 
ammoniacal,  and  nitric  combinations.  Carried  out  in  the  same 
way  as  the  Yarentrapp  -Will  method  in  Peligot's  modification. 
The  method  has  been  well  sustained.  DABNEY  (1885,  already 
cited)  found  this  method,  in  application  to  fertilizers  containing 
small  amounts  of  nitrogen,  to  give  results  as  close  as  those  by 
Johnson's  process  for  free  nitrogen,  the  latter  method  giving 
often  a  little  too  high,  the  former  a  little  too  low  figures  for 
the  nitrogen.  Greater  precautions  are  required  for  bodies  rich 
in  nitrogen.  Details  are  presented  in  the  Official  Methods  of  the 
Association  of  Agricultural  Chemists  for  1886-7,  Bulletin  No. 
12,  Department  of  Agriculture,  Washington,  1886. 

RELATIVE  DETERMINATION  OF  THE  NITROGEN  AND  CARBON. — 
Applicable  when  the  proportional  quantity  of  nitrogen  is  not 
small,  or  not  less  than  1ST  to  4  C  =  14  of  nitrogen  to  48  of  car- 
bon. The  substance  is  burned,  with  copper  oxide,  and  the 
products  passed  over  hot  metallic  copper,  in  a  combustion- 
tube,  so  as  to  deliver  in  a  graduated  tube  the  nitrogen  and 
the  carbon  dioxide.  After  taking  the  volume  measure  of  the 
gases  the  carbon  dioxide  is  taken  up  by  alkali  and  measurement 
taken  again.  Methods  of  Liebig,  Bunsen,  and  Gottlieb  are 
employed. 

THE    DETERMINATION  OF  CARBON,  HYDROGEN,  AND   NITROGEN,  in 

one  operation,  is  described  by  C.  G.  WHEELER,  1866  :  Am.  Jour. 
Sci.,  [2],  41,  33.  Also  by  W.  HEMPEL,  1878 :  Zeitseh.  anal. 
Chem.,  17,  409;  Jour.  Chem.  Soc.,  36,  278.  Recently  by  P. 
JANNISCH  and  Y.  MEYER,  1886:  Ber.  d.  chem.  Gesel.,  19,  949 
(preliminary  notice). 

also  JOHNSON,  1879:  Am,  Chem.  Jour.,  i,  82. 


234  ELEMENTAR  Y  ANAL  YSIS. 

THE  DIRECT  ESTIMATION  OF  OXYGEN  lias  been  reported  upon  as 
follows :  BAUMHAUER,  1866 ;  MAUMENE,  1862 ;  MITSCHERLICH, 
1867,  1868;  LADENBURG,  1865;  CRETIER,  1874. 

ESTIMATION  OF  NITROGEN  BY  COMBUSTION  IN  THE  MOIST  WAY. 
— The  well-known  process  published  by  Prof.  WANKLYN  in  1877 
depends  on  the  conversion  of  the  nitrogen  of  organic  compounds 
into  ammonia  by  the  action  of  permanganate  in  a  very  dilute 
solution  of  alkaline  reaction,  the  ammonia  already  contained  in 
the  substance  being  previously  distilled  off.  Its  value,  in  water 
analysis,  is  relative  rather  than  absolute,  and  depends  upon  its 
applicability  to  nitrogenous  organic  compounds  in  an  extremely 
dilute  solution,  so  that  the  changes  likely  to  occur  in  a  concen- 
tration of  the  water  are  avoided.  For  the  analysis  of  pure  ni- 
trogenous compounds  various  plans  of  moist  combustion  have 
been  proposed  of  late  years.  Of  these  the  following  method  has 
received  general  commendation  from  chemists  who  have  reported 
trials  of  it — a  method  in  which  oxidation  by  adding  dry  perman- 
ganate to  a  concentrated  acid  solution  is  preceded  by  the  altera- 
tive action  of  hot  sulphuric  acid  of  full  strength : 

Moist  Method  of  KJELDAHL/ — For  bodies  moderately  rich 
in  nitrogen  0.250  gram  is  taken  ;  for  bodies  with  only  about  1.5# 
of  nitrogen  0.7  gram  is  taken.  The  substance  is  placed  in  a  boil- 
ing-flask of  about  100  c.c.  capacity,  with  a  long  and  narrow  neck, 
and  of  glass  capable  of  resisting  the  strongest  acids.  The  flask  is 
placed  upon  asbestos  cloth  or  copper  gauze  over  a  lamp  supplying 
a  strong  heat,  10  c.c.  of  pure  sulphuric  acid  of  full  strength  is 
added,  and  digestion  instituted  (under  a  hood)  at  a  temperature 
.only  a  little  below  the  boiling  point  of  the  sulphuric  acid. 
Sulphurous  acid  vapors  escape.  To  prevent  loss  by  spirting,  the 
flask  is  somewhat  inclined  during  the  effervescence.  After  the 
liquid  comes  to  rest  the  digestion  is  continued  (still  near  the 
boiling  point,  as  shown  by  occasional  bumping)  until  the  liquid 
becomes  gradually  of  light  color,  and  finally  entirely  clear.  To 

1  J.  KJELDAHL,  Carlsberg  Laboratory  of  Copenhagen,  1883:  Zeitsch.  anal 
Chem.,  22,  366;  Ohem.  News,  48,  101;  Am.  Chem.  Jour.,  5,  456.  FRESENIUS* 
1884:  Zeitsch  anal.  Chem.,  23,  £53.  CZECZETKA,  1886:  Monatsch  Chem  ,  6 
68;  Jour.  Chem.  Soc.,  48,  688.  WILFARTH,  1885:  Chem.  Cent.,  1885,  17; 
Jour.  them.  Soc.t  48,  837.  BOSSHARU,  1886:  Zeitsch.  anal.  Chem.,  24,  199; 
Jour.  Chem.  Soc.,  48,  837.  0.  ARNOLD,  1886:  Archiv  d.  Pharm..  [3],  23,  177; 
Jour.  Chem.  Soc  48,  688.  Details  are  defined  in  the  "  Official  Methods  of  the 
Association  of  Agricultural  Chemists,"  Department  of  Agriculture,  Bulletin 
No.  12,  Washington,  1886.  The  use  of  phenolsu! phonic  acid  is  introduced  into 
the  process  by  JODLBAUEE.  1886:  Chem.  Cent.,  p.  433;  Jour.  Chem.  Soc.,  50, 


ESTIMA  TION  OF  NITROGEN.  235 

hasten  this  result  a  little  fuming  sulphuric  acid  or  phosphoric 
anhydride  is  added.  With  these  additions  a  digestion  of  about 
two  hours  is  usually  sufficient.  But  at  100°  to  150°  C.  the  for- 
mation of  ammonia  is  imperfect  and  the  object  not  attained. 
The  lamp  is  now  removed,  and,  while  the  liquid  is  hot,  finely 
pulverized  potassium  permanganate  is  carefully  added,  either  in 
very  small  portions  or  in  a  very  fine  stream,  which  may  be  car- 
ried through  a  delivery-tube.  The  reaction  is  violent,  even  ac- 
companied by  small  flames,  and  it  is  made  as  gradually  as  it  can 
be  without  interrupting  it.  When  the  oxidation  is  complete  a 
green  color  appears,  and  the  addition  of  the  permanganate  is  dis- 
continued. The  liquid  may  now  be  warmed  for  a  few  minutes, 
but  not  on  any  account  strongly  heated.  The  liquid  is  cooled, 
and  diluted  with  water,  when  the  green  color  changes  to  brown. 

When  again  cool  the  liquid  is  introduced  into  a  distillatory 
apparatus,  the  generating  flask  holding  about  f  liter,  and  con- 
nected with  an  upward-sloping  top-piece  to  prevent  liquid  being 
carried  over  by  spirting,  and  through  the  condenser  into  a  re- 
ceiver containing  an  accurately  measured  quantity  of  acid  of 
known  strength.  About  40  c.c.  of  solution  of  sodium  hydrate 
of  sp.  gr.  1.30  are  quickly  introduced  into  the  distilling  flask. 
[A  Welter's  safety  tube  may  be  provided  for  this  purpose.] 
And  to  prevent  bumping  a  little  metallic  zinc  is  introduced, 
the  hydrogen  from  which  secures  an  even  action. 

The  completed  distillate  is  titrated  for  the  ammonia  it  has 
received  (as  in  the  estimation  of  Varentrapp  and  Will). 

Kjeldahl  found  his  method  inapplicable  to  -certain  alkaloids, 
cyanides,  volatile  acids,  and  nitrogen  oxides.  It  reduces  nitrates 
in  presence  of  organic  matter  to  ammonia,  but  incompletely  (com- 
pare WARINGTON,  1885 :  CJiem.  News,  52,  162). 

Upon  the  Determination  of  Total  Nitrogen,  organic,  am- 
moniacal,  and  nitrous,  see  BULLETIN  No.  12,  Chemical  Division, 
DEPARTMENT  OF  AGRICULTURE,  Washington,  1886,  pp.  34,  52. 
Also,  GERMAN  MANURE  MANUFACTURERS'  ASSOCIATION,  1884: 
H.  H.  B.  Shepherd,  translator.  Also,  HOUZEAU,  1885.  RUF- 
FLE'S method  to  this  effect  is  referred  to  on  p.  233. 

BODIES  CONTAINING  SULPHUR,  in  estimation  of  carbon  and 
hydrogen,  are  subjected  to  combustion  with  lead  chromate  in- 
stead of  copper  oxide,  and  the  front  of  the  column  of  lead  chro- 
mate is  not  heated  to  full  redness. — WHEN  CHLORINE,  BROMINE, 
or  IODINE  is  present,  in  combustion  to  estimate  carbon  and  hy- 
drogen, a  coil  of  silver  wire  is  placed  in  the  front  of  the  combus- 
tion-tube to  retain  the  halogens,  which  otherwise  may  interfere 


236  ELEMENTARY  ANALYSIS. 

with  the  result.  Chlorine  forms  cuprous  chloride,  which  will 
condense  in  the  calcium  chloride  tube.  Copper  holds  chlorine 
but  imperfectly,  and  the  same  is  true  of  lead. 

4 

THE  ESTIMATION  OF  SULPHUR,  in  organic  analysis  of  com- 
pounds not  volatile,  may  be  done  by  fusing  with  potassium  hy- 
drate and  nitrate,  in  a  silver  dish,  until  the^mass  will  be  white 
on  cooling.  The  mass  is  dissolved  in  water,  acidified  by  nitric 
acid,  and  the  quantity  of  sulphuric  acid  determined  by  precipita- 
tion with  barium  chloride  in  the  manner  required  in  quantitative 
work.  Volatile  compounds  can  be  oxidized  with  a  mixture  of 
sodium  carbonate  and  potassium  nitrate  in  a  combustion-tube. 
Potassium  dichromate  is  also  employed  as  an  oxidizing  agent  in 
the  same  way. 

CHLORINE,  BROMINE,  and  IODINE  are  estimated  by  igniting  the 
substance  with  an  excess  of  pure  quicklime,  in  a  narrow  combus- 
tion-tube. The  tube  is  filled  with  the  lime  mixed  with  the  sub- 
stance, followed  by  a  short  column  of  lime  alone,  and  a  channel 
made  by  tapping  the  tube  on  the  table.  After  the  ignition  the 
contents  of  the  tube,  when  cold,  are  carefully  transferred  to  a 
flask  containing  water,  and  treated  with  dilute  nitric  acid,  rinsing 
the  tube  with  the  water  and  then  with  the  acid.  The  solution  is 
filtered,  the  residue  and  filter  washed,  and  the  halogens  precipi- 
tated by  silver  nitrate  solution.  With  iodine  it  is  better  to  ex- 
haust first  with  water,  and  add  silver  nitrate  solution  to  the 
filtrate,  then  treat  the  residue  with  dilute  nitric  acid  and  add 
the  acidulous  filtrate  to  the  one  containing  the  silver.  By  this 
means  the  liberation  of  iodine  by  action  of  nitric  acid  is  avoided. 
The  silver  precipitate  is  treated  as  in  ordinary  quantitative  work 
for  the  halogens. 

ESTIMATION  OF  SULPHUR  OR  OF  HALOGENS  is  effected  by  the 
method  of  CARIUS  1  From  0.15  to  0.40  gram  of  the  substance 
is  treated  with  a  calculated  quantity  of  nitric  acid  sufficient  to 
furnish  4  times  the  required  amount  of  available  oxygen,  or  of 
acid  of  sp.  gr.  from  20  to  60  times  the  weight  of  the  substance. 
The  digestion  is  done  in  a  closed  tube,  sealed,  at  120°  to  140°  C., 
for  some  hours.  For  estimation  of  chlorine,  silver  nitrate  is 
added  with  the  nitric  acid  before  digesting.  Details  may  be 
found  in  the  original  papers  and  in  manuals  of  quantitative 
analysis. 

1 1860-65:  Ann.  Chem.  Phar.,  116,  11;  136,  129;  Zeitsch.  anal.  Chem.,  i 
217,240;  4,  451;  10,  103. 


DEDUCTION  OF  CHEMICAL  FORMULAE.      237 

DEDUCTION  OF  CHEMICAL  FORMULAE. — In  the  first  place,  the 
molecular  weight  of  the  substance  is  to  be  ascertained,  if  possible. 

(1)  If  the  compound  be  sufficiently  vaporizable  its  Vapor 
Density  1  is  to  be  determined  and  accepted  as  evidence  of  the 
molecular  weight.     With  the  weight  of  air  as  the  unit  of  gravi- 
ties, vapor  density  X  28. 86  =  molecular  weight.     With  hydrogen 
as  the  unit,  vapor  density  X  2  —  molecular  weight. 

(2)  If  the  substance  have  a  definite  capacity  of  combining,  as 
a  base  or  an  acid,  its  combining  number  can  be  determined  by  its 
proportions  in  formation  of  salts.     If  an  acid,  it  is  needful  to 
ascertain   whether  it  be  monobasic,   bibasic,   or   tribasic  in  its 
capacities  of  combination.     Certain  classes  of  bases  are  subject 
to  the  corresponding  question,  whether  nionacid  or  not,  but  the 
natural  nitrogenous  bases  are  mostly  monacid. 

(3)  If  the  substance  be  found  to  hold  a  definite  relation  to 
other  substances,  as  shown  by  its  formation,  its  decomposition, 
or  by  chemical  resemblance  to  members  of  homologous  series,  its 
molecular  weight  may  be  inferred  from  such  relations. 

If  now  m  be  the  molecular  weight  of  a  compound ; 
p,  the  percentage  of  a  constituent  element ; 
a?,  the  combining  number  of  this  element ; 
#,  its  atomic  weight,  and 
y,  the  number  of  its  atoms  in  the  molecule, 
100  :  p  : :  m  :  x.     And  x  -h  a  =  y. 

Whether  the  molecular  weight  be  obtainable  or  not,  an  empi- 
rical statement  of  atomic  numbers  can  be  derived  at  once  from 
the  centesimal  figures  of  the  analysis  by  dividing  the  percentage 
number  of  each  element  by  its  atomic  weight.  The  provisional 
formula  so  obtained  is  reduced,  by  common  divisors,  to  lower 
terms,  and  to  such  terms  as  best  accord  with  its  probable  molecu- 
lar weight,  in  its  apparent  classification  among  compounds  of 
known  molecular  formulae. 

Allowances  must  be  made  for  the  real  limits  of  error  in 
analysis,  and  consideration  must  be  had  to  the  liability  of  weigh- 

1  For  ordinary  purposes  the  most  ready  and  satisfactory  method  of  obtain- 
ing Vapor  Density  is  that  of  VICTOR  and  CARL  MEYER,  1878:  Ber.  d.  chem. 
&es.,  10,  2253;  Zeitsch.  final.  Chem.,  19,  214;  "Watts's  Diet.  Chem,"  8,  2094. 
.See  also  reports  by  V.  MEYER,  1876-7:  Ber.  d.  chem.  Oes.,  9,  1216;  10,  2067; 
11,  1867;  Zeitsch.  anal.  Chem.,  18, 294;  17,  373.  HOFM  ANN'S  Method  was  given 
in  1868:  Ber.  d  chem.  Ges.,  i,  198;  Zeitsch.  anal.  Chem.,B,  83.  BUNSEN'S 
Method,  1867:  Ann.  Chem.  Phar.,  141,  273:  Zeitsch.  anal.  Chem.,  6,  1. 
Method  of  TROOST  and  DEVILLE,  1860:  Ann.  Chim.  Phys.,  [3],  58,  257.  A 
good  summary  of  the  literature  of  vapor-density  determination  is  given  in 
"Roscoe  and  Schorlemmer's  Chemistry,"  vol.  3,  part  1,  p.  84  and  after.  Also 
see  "  Beilstein's  Organische  Chemie,"  2d  ed.,  p.  17. 


238  FA  TS  AND   OILS. 

able  impurities,  including  moisture,  in  the  article  taken  for  com- 
bustion. Probable  limits  of  error  are  represented  in  general  by 
a  comparison  of  published  results  of  analyses  by  authorities  of 
credit,  and,  more  definitely,  by  the  experience  of  the  analyst 
himself  with  substances  of  known  composition. 

Even  in  empirical  formulae  the  well-known  law  of  conjugate 
atomic  numbers  of  carbon  compounds  should  be  respected, 
namely,  the  numbers  of  the  atoms  of  uneven  valence  (the  perissads, 
H  and  N)  should  together  make  an  even  number.  Thus  in  the 
molecule  of  morphine,  with  'N1  we  have  H19 ;  in  the  molecule  of 
quinine,  with  JsT2  we  have  H24-  That  is,  in  ordinary  non-nitro- 
genous organic  molecules,  those  containing  C,  H,  and  O,  or  those 
containing  C  and  H,  there  is  always  an  even  number  of  atoms  of 
hydrogen.  But  in  nitrogenous  molecules  (of  C,  H,  IS",  O,  or 
C,  H,  N)  the  atomic  number  of  hydrogen  is  even  only  when 
nitrogen  presents  an  even  atomic  number.  The  law  applies  to 
haloid  elements  and  to  phosphorus,  when  these  elements  of  un- 
even valence  are  present. 

The  low  atomic  weight  of  hydrogen  gives  low  centesimal  dif- 
ferences for  one  atom  of  this  element,  so  that  its  atomic  number 
is  taken  as  the  number  which,  under  the  rule,  lies  nearest  the 
atomic  number  calculated  from  centesimals. 

The  establishment  of  a  rational  formula  for  a  compound  is 
a  work  of  investigation,  both  synthetic  and  analytic,  as  obtained 
by  reactions  of  formation  and  of  decomposition.  It  requires 
studies  of  all  chemical  relations,  led  on  by  analogies  from  every 
point  of  view.  An  understanding  of  the  chemical  structure  of 
the  molecule  is  gained  step  by  step  in  the  investigation.  A  de- 
rived chemical  formula  can  be  made  "rational"  only  to  the  extent 
that  the  chemical  forces  of  the  constituent  elements  have  been 
revealed  in  their  proportional  power.  In  the  study  of  isome- 
rides,  for  the  "  position  "  of  atoms  in  molecules,  the  atomic  posi- 
tion is  to  be  defined  as  a  mode  of  statement  of  the  chemical 
functions  of  the  elements.  At  the  same  time  it  may  be  said  that 
the  evidence  gained  for  relative  u  position  "  of  atoms  in  a  mole- 
cule is  of  the  same  character  as  the  evidence  upon  which  we 
predicate  the  existence  of  the  molecule  as  a  whole. 

FATS  AND  OILS.1— Glycerides,  and  bodies  related  thereto 

1 A  good  general  summary  of  the  chemistry  and  technology  of  the  neutral 
fats  is  presented  in  the  article  "Chemical  and  Analytical  Examination  of 
Fixed  Oils,"  A.  H.  ALLEN,  1883:  Jour.  Soc.  Ohem.  Indus.,  2,  49.— A  compact 
technical  summary  of  the  analytical  chemistry  of  fats  is  presented  in  BENE- 
DIKT'S  "  Analyse  der  Fette  und'Wachsarten,"  Berlin,  1886,  pp.  296. 


FATTY  SERIES   OF  ACIDS.  239 

either  by  physical  properties  and  uses  or  by  production,  are  treat- 
ed in  the  following  pages  under  the  heads  here  given  : 

Fatty  Series,  CnHan02:  Stearic  Acid ;  Palmitic  Acid;  Myristic,  Laurie, 
Capric,  Caprylic,  Caproic  acids. 

Fatty  Series,  CnH2n_202 :    Oleic  Acid. 

Ricinoleic  Acid  ;  Linoleic  Acid  ;  Hypogaic  and  Physetoleic  acids. 

Fat  Acids  and  Fats,  Quantitative  Determination  of :  (1)  Hehner's  num- 
ber; (2)  Reichert's  number;  (3)  Kottstorfer's  number,  or  capacity  of  saturation; 
Tables  of  Hehner's  and  Kottstorfer's  numbers;  (4)  Iodine  number  of  Hiibl:  (5) 
Mean  Molecular  Weight;  (6)  Specific  Gravities;  (7)  Melting  and  Congealing 
points;  (8)  Calculation  of  Acid  and  Neutral  Fats. 

Distinctions  of  Fat  Oils  by  Solubility  in  Glacial  Acetic  Acid ;  Table. 

Separation  of  Mineral  Oils  from  Fats:  descriptive  list;  method  by  saponi- 
fication;  extraction  after  saponification,  in  solution,  in  dry  mass,  with  Soxlet's 
apparatus,  estimation  by  Kottstorfer's  numbers ;  examination  of  the  liquid  and 
solid  non-saponifiable  bodies. 

Separation  of  Fat  Acids  from  Fats. 

Separation  of  Resins  from  Fat  Acids. 

Rosin  Oils. 

Drying  and  Non-Drying  Oils. 

Linseed  Oil;  Olive  Oil;  Cotton-seed  Oil ;  Castor  Oil;  Lard;  Tallow;  Oleo- 
margarin. 

Butter:  bibliography:  constituents;  estimation  of  constituents,  of  artificial 
color,  or  rancidity  (acidity);  detection  of  foreign  fats  by  solvents;  Scheffer's 
method;  odor  test;  soap  viscosity  ;  microscopical  examinations;  butter  fat, 
properties:  butter  substitutes ;  methods  of  chemical  estimation  of  butter  fat- 
Header'*,  Reichert's,  Kottstorfer's;  interpretation  of  Hehner's  number,  of 
Reichert's,  of  Kottstorfer's;  specific  gravity  as  a  means  of  distinguishing  from 
substitutes;  iodine  number  of  Hilbl;  scope  of  butter  analysis  and  forms 
of  certificates,  in  Massachusetts,  in  New  York,  in  Pennsylvania,  at  Agricul- 
tural Department  at  Washington;  what  is  a  sufficient  chemical  analysis  of 
butter. 

FATTY  SERIES  OF  ACIDS,  CnH2nO2. — The  folio  wing- named 
members  of  the  CnIl2nO2  series  are  described  in  this  work,  and 
will  be  found  under  their  respective  names.  Formic,  Acetic, 
and  Yaleric  Acids  are  not  constituents  of  Fats.  The  others  are 
described  in  the  next  following  pages.  For  Butyric  Acid  see 
p.  75. 

Volatile. 

Formic  Acid CH2O2  or  H .  CO2H 

Acetic  Acid C9H4O2  "  CH3.CO2H 

Butyric  Acid— normal. .   C~4HSO2  "  CH3CH2CH2.CO2H 

Yaleric  Acid— isovaleric.  C5H10O2  "  (CH3)2CH  CH2 .  CO2H 
Caproic  Acid — isobutyl- 

acetic C6H1202  «  (CH3)2CH(CH2)2 .  CO2H 

Caprylic  Acid— normal.   C8H16O2  "  CH3(CH2)6.CO2H 

Capric  Acid C10H20O2  «  CH3(CH2)8.CO2H ? 

Laurie  Acid C12H24O2 


240  FATS  AND  OILS. 

Non-  Volatile. 

Mjristic  Acid. C14H28O2 

Palmitic  Acid C16H32O3 

Stearic  Acid C18H3gO2 

STEAEIO  ACID. — C18H36O2=:284  (monobasic).  Found  as  a 
normal  glyceride  in  common  vegetable  and  animal  fats,  in  which 
it  is  the  ordinary  constituent  of  highest  melting  point. 

a.— Crystallizable  from  alcohol  in  white,  lustrous  tables,  or 
needles;  or  congealing  from  a  melted  portion  in  crystalline, 
translucent  masses  of  considerable  hardness.  It  melts  at  69.2°  C. 
At  about  360°  C.  it  begins  to  boil  with  decomposition  of  a  con- 
siderable part.  Under  reduced  pressure,  at  100  millimeters,  it 
boils  at  291°  C.  With  superheated  steam  it  distils  with  but  lit- 
tle decomposition.  Its  specific  gravity  as  a  solid  at  11°  C.  is 
that  of  water  at  the  same  temperature,  but  at  higher  tempera- 
tures it  floats  upon  water,  and  the  melted  acid  just  above  69.2°  C. 
has  the  specific  gravity  of  0.8454. 

The  melting  paint  can  be  found,  quickly,  by  immersing  the 
bulb  of  the  thermometer  for  a  moment  in  the  melted  stearic  acid 
(free  from  water),  then  suspending  the  coated  bulb  in  the  middle 
of  a  beaker  of  water,  to  which  heat  is  applied,  and  noting  the  tem- 
perature at  which  the  fatty  coat  melts  from  the  bulb.  To  purify 
stearic  acid  from  salts,  preparatory  to  this  test,  it  may  be  repeat- 
edly dissolved  in  alcohol,  filtered,  and  evaporated  to  dryness. 
(Further,  see  Determination  of  the  Melting  and  Congealing 
Points  of  Fatty  Bodies,  Index.) 

The  normal  glyceride,  stearin,  or  "  tristearin,"  C3H5 
(C18H35O2)3,  is  crystallizable,  and,  when  pure,  of  pearly- white 
lustre.  It  melts,  according  to  modification  due  to  previous  heat- 
ing, at  a  temperature  from  55°  C.  to  71.6°  C.  Stearin  crystal- 
lized from  ether  melts  at  71.6°  C.,  and  then  congeals  to  a  crys- 
talline mass  at  70°  C. ;  but  heated  only  4°  C.  above  the  melting 
point,  it  does  not  then  congeal  until  reduced  to  the  temperature 
of  about  52°  C.,  when  it  appears  as  a  wax-like  mass  and  will 
melt^ again  at  55°  C.  A  sample  of  stearin  (not  entirely  pure), 
melting  at  65. 5°  C.,  at  this  temperature  had  the  specific  gravity 
0.9245  (BENEDIKT  '). 

The^  metallic  stearates  are  fusible  bodies,  in  some  instances 
crystallizable,  more  often  amorphous,  and  of  plaster- like  or  soap- 
like  consistence. 

b . — Stearic  acid  and  stearins  are  odorless  and  tasteless. 
1  "Analyse  der  Fette,"  Berlin,  1886. 


STEARIC  ACID.  241 

c'. — Stearic  acid  is  insoluble  in  water.  It  is  soluble  in  about 
40  parts  of  absolute  alcohol  at  ordinary  temperatures,  moderate- 
ly soluble  in  90$  alcohol  when  hot,  very  sparingly  when  cold. 
On  cooling  the  hot  alcoholic  solution  abundant  crystals  are  ob- 
tained. It  is  readily  soluble  in  ether.  The  solutions  redden  lit- 
mus-paper, and  decolor  the  alkaline  phenol-phthalein.  At  23°  C. 
it  dissolves  in  4.5  parts  of  benzene  or  in  3.3  parts  of  carbon  di- 
sulphide. 

Stearin,  the  neutral  glyceride,  is  insoluble  in  water,  some- 
what soluble  in  boiling  alcohol,  from  which  it  crystallizes  out 
almost  wholly  when  cold.  It  dissolves  'in  about  200  parts  of 
ether— a  solubility  more  sparing  than  that  of  the  softer  neutral 
fats — and  dissolves  in  chloroform,  benzene,  petroleum  benzin, 
and  carbon  disulphide. — The  alkali  stearates  are  somewhat  dif- 
ficultly and  imperfectly  soluble  in  water.  They  dissolve  in  hot 
water,  with  slight  turbidity,  the  solution  gelatinizing  when  cold. 
On  agitating  the  gelatinized  mass  with  much  water  in  the  cold, 
a  turbid  mixture  is  obtained,  with  formation  of  difficultly  soluble 
acid  stearate  along  with  free  alkali.  In  hot  alcohol  the  alkali 
stearates  are  easily  soluble,  the  greater  part  congealing  in  the 
cold,  so  that  only  a  dilute  solution  is  permanently  obtained. 
The  non-alkali  metallic  stearates  are  insoluble  in  water,  and  for 
the  most  part  insoluble  in  alcohol  or  ether.  In  some  instances, 
however,  they  yield  free  stearic  acid  to  the  action  of  ether.  In 
general  they  are  gradually  decomposed  by  action  of  water,  yield- 
ing hydrate  of  the  metal  and  free  stearic  acid. 

d. — The  aqueous  solutions  of  alkali  stearates,  dilute  and 
turbid,  on  addition  of  solution  of  barium  or  calcium  chloride, 
or  other  non-alkali  salt,  show  an  abundant  precipitate  of  metallic 
stearate.  An  alcoholic  solution  of  stearic  acid,  with  a  solution 
of  barium  or  calcium  acetate  to  which  a  little  alcohol  has  been 
added,  gives  a  precipitate  of  stearate  of  the  metal.  The  barium 
precipitate  is  gelatinous  and  bulky ;  the  magnesium  precipitate, 
crystalline  and  pulverulent.  To  the  action  of  water  these  pre- 
cipitates yield  hydrates  of  barium,  etc.,  while  free  fat  remains 
behind.  The  precipitates  are  to  some  extent  dissolved  by  boil- 
ing alcohol,  and  on  cooling  the  solution  crystalline  precipitates 
are  obtained. — Solutions  of  alkali  stearates  are  precipitated  by 
addition  of  dilute  acids,  the  resulting  stearic  acid  appearing  in  a 
milky  subdivision  with  curdy  clumps.  By  heating  the  mixture 
a  clear,  oily  layer  slowly  rises,  and  on  cooling  solidifies  to  a  crust. 
Or  the  precipitate  while  cold  may  be  filtered  out,  washed  with 
hot  water,  drained  dry,  and  dissolved  from  the  filter  with  hot 


242  FA  TS  AND   OILS. 

alcohol  or  with  cold  ether.  On  evaporation  the  stearic  acid  is 
obtained,  crystalline  or  congealed,  as  preferred.  Also  the  crude 
precipitate  of  stearic  acid  may  be  dissolved  by  shaking  out  with 
several  portions  of  ether. 

e. — Separation. — Stearic  acid  is  obtained  from  its  glyceride, 
stearin,  by  first  saponifying  with  potash,  and  then  decomposing 
the  soap  with  acid.  The  saponification  is  done  by  boiling  gently 
with  alcoholic  solution  of  potassa  until  a  clear  solution  is  ob- 
tained. Ten  parts  of  the  fat  are  treated  with  8  to  10  parts  of 
70  to  85$  alcohol,  and  4  to  6  parts  solid  potassa.  The  most  of 
the  alcohol  is  evaporated  off,  and  the  cold  liquid  treated  with 
dilute  acid  for  liberation  of  the  stearic  acid,  as  directed  above 
(d).  From  non-alkali  stearates,  acidulating  with  an  acid  that 
does  not  precipitate  the  metal,  and  shaking  out  with  ether,  is 
usually  the  most  expeditious  method  of  separating  the  stearic 
acid. 

From  oleic  acid  stearic  acid  (with  other  solid  fat  acids)  is 
separated  T)y  insolubility  qf  lead  stearate  in  ether,  as  follows. 
The  free  fat  acids  are  to  be  perfectly  saponified  with  potassa 
or  soda ;  the  neutral  solution  of  the  alkali  soap,  with  some  alco- 
hol, is  precipitated  with  lead  acetate,  and  the  precipitate  washed, 
dried,  and  exhausted  with  ether  in  repeated  portions,  when  the 
lead  salts  of  the  solid  fat  acids  will  be  left  undissolved,  and  the 
lead  oleate  can  be  obtained  by  evaporating  the  ethereal  solution. 
The  details  may  be  governed  as  follows  (]£REMEL  *).  Of  the  free 
fat  acids  2  to  £  grams  are  exactly  weighed  into  a  flask  of  100 
to  150  c.c.  capacity,  treated  with  about  an  equal  quantity  of  dry 
caustic  potash  and  10  c.c.  of  alcohol  of  &5  per  cent,  strength, 
on  the  water-bath,  to  complete  saponification.  The  mass  is  di- 
luted with  a  little  water,  neutralized  with  acetic  acid,  using 
phenol-phthalein  as  an  indicator,  the  alcohol  evaporated  off  on 
the  water-bath,  the  residue  dissolved  in  80  c.c.  hot  water,  and 
the  liquid  precipitated  with  lead  acetate  solution.  When  cold 
the  free  precipitate  is  poured  upon  a  filter  of  10  cm.  (near  4 
inches)  diameter,  and  the  whole  precipitate  is  washed  several 
times  with  hot  water.  The  precipitate  adhering  to  the  flask  is 
melted  on  the  water-bath,  cooled,  drained,  and  dried  at  a  gentle 
heat,  as  is  also  the  precipitate  in  the  filter.  The  contents  of  the 
flask  are  now  treated  with  ether,  poured  through  the  same  filter, 
in  repeated  portions,  until  the  whole  precipitate  is  exhausted 
of  ether-soluble  substance.  On  vaporizing  the  ether  in  the 
filter  the  lead  stearate  can  be  detached,  and  added  to  that  in  the 

1  Consult  also  MUTER  :  Analyst,  2,  73. 


STEARIC  ACID.  243 

flask,  where  the  whole  is  treated  with  diluted  hydrochloric  acid, 
and  exhausted  with  ether.  The  liltered  ethereal  solution  is  eva- 
porated in  a  tared  beaker  and  the  residue  weighed  as  stearic  acid 
(including  all  solid  fat  acids).  For  the  oleic  acid  (the  total  of 
liquid  fat  acids)  the  ethereal  solution  of  lead  salt  is  evaporated 
to  dry  ness,  and  the  residue  treated  with  diluted  hydrochloric 
acid  and  then  with  ether,  as  directed  for  the  solid  fat  acids. 

Stearic  acid  (with  palmitic  acid)  is  separated  from  oleic  acid 
by  tJie  solvent  action  of  a  mixture  of  alcohol  and  glacial  acetic 
acid  (DAVID,  1878  1).  In  the  proportion  of  300  c.c.  of  alcohol 
of  95  per  cent,  strength  with  220  c.c.  of  glacial  acetic  acid,  at 
15°  C.,  the  oleic  acid  is  just  soluble,  while  the  solid  fat  acids  are 
insoluble.  A  greater  proportion  of  the  acetic  acid  precipitates 
oleic  acid  from  its  alcoholic  solution  ;  a  smaller  proportion  per- 
mits the  solution  of  stearic  and  palmitic  acids.  A  weighed 
portion  of  one  or  two  grams  of  the  fat  acids  under  examination, 
in  a  flask  provided  with  a  tight  stopper,  is  treated  with  the  sol- 
vent mixture,  in  twenty-four  hours'  digestion  at  about  15°  C., 
with  occasional  shaking.  The  mixture  is  then  filtered,  washed 
first  with  the  solvent  mixture,  then  with  cold  water,  gathered 
into  a  weighed  dish,  melted,  drained  of  water,  dried  in  a  desic- 
cator or  at  100°  C.,  and  weighed  as  stearic  acid. 

f. —  Quantitative. — Free  stearic  acid,  in  absence  of  other  acids, 
or  a  total  of  fat  acids  to  be  estimated  as  stearic  acid,  may  be  de- 
termined in  quantity  by  acidimetry,  using  phenol-phthalein  or 
litmus  as  an  indicator,  and  taking  the  fat  acid  in  alcoholic  solu- 
tion. Each  c.c.  of  normal  solution  of  alkali  represents  0.284 
gram  of  stearic  acid.  Taking  2.84  gram  of  the  material  under 
estimation,  each  c.c.  of  decinormal  solution  of  alkali  equals  1  per 
cent,  of  free  stearic  acid. 

Free  stearic  acid,  as  obtained  by  precipitating  an  alkali  stear- 
ate  in  aqueous  solution  with  a  diluted  acid,  washing  with  water, 
melting  to  separate  water,  and  drying,  may  be  weighed  as 
C18H36O3.  Also  the  residue  of  its  ethereal  solution  may  be 
melted,  brought  to  a  constant  weight,  and  weighed  in  the  same 
way. 

From  Oleic  acid  stearic  acid  is  separated  as  directed  under 
0,  p.  242 ;  in  mixture  with  Palmitic  acid  stearic  acid  is  estimated 
by  methods  given  under  Fat  Acids,  Quantitative  Determinations 
of,  (5)  and  (7),  p.  250. 

g. — Stearic  acid  is  the  u  stearin  "  of  the  candle  industry. 

1  Ding.  pol.  Jour.,  231,  64;  Zeitsch.  anal.  Chem.,  18,  622;  Benedikt's 
"Analyse  der  Fette  "  (1886),  p.  81;  Am.  Jour.  Phar.,  55,  356. 


244  FATS  AND   OILS. 

For  determinations  of  commercial  value  see  under  reference  last 
given,  especially  methods  (4)  to  (8). 

PALMITIC  ACID. — C16H32O2  =  256  (monobasic).  Margaric 
Acid.1  Found  as  a  normal  glyceride  in  ordinary  vegetable  and 
animal  fats. 

a. — As  free  acid,  crystallizable  from  alcoholic  solution  in 
fine  needles,  sometimes  grouped  in  sheaves,  or  congealing  from 
a  melted  mass  in  partly  crystalline  forms  of  pearly  lustre.  Melts 
at  62°  C.,  at  which  temperature  the  liquid  has  the  sp.  gr.  0.852T. 
At  about  350°  C.  it  distils  with  partial  decomposition.  It  leaves 
a  permanent  oil  stain  on  paper.  Under  the  reduced  pressure  of 
100  millimeters  it  distils  at  268.5°  C.— The  glyceride,  Palmitin, 
C3H5(C16H31O2)3 ,  is  crystallizable,  in  pearly  lustrous  forms. 
It  melts  at  temperatures  from  50.5°  to  66.5°  C.,  according  to 
its  previous  exposure  fo  heat.  Strongly  heated  it  carbonizes 
abundantly. 

~b. — Palmitic  acid,  as  well  as  palmitin,  is  odorless  and  of  a 
bland,  oily  taste. 

c. — Palmitic  acid  is  insoluble  in  water,  and  but  sparingly  and 
slowly  soluble  in  cold  alcohol,  requiring  10.7  parts  of  absolute 
alcohol  for  solution,  but  hot  alcohol  dissolves  it  more  freely, 
yielding  crystals  as  the  solution  cools.  It  dissolves  freely  in 
ether.  The  alcoholic  solution  has  an  acid  reaction. 

The  normal  glyceride,  palmitin,  is  but  slightly  soluble  in  cold 
alcohol,  moderately  soluble  in  hot  alcohol,  and  soluble  in  ether, 
chloroform,  benzene,  petroleum  benzin,  and  in  carbon  disulphide. 

Alkali  palmitates  (soaps  of  palmitin)  are  soluble  in  water, 
with  tendency  to  turbidity  from  slight  decomposition,  increased 
by  dilution ;  more  permanently  soluble  in  alcohol,  scarcely  at  all 
soluble  in  ether. — ^Ton-alkali  metallic  palmitates  are  insoluble  in 
water  or  ether.  Lead  palmitate  is  insoluble  in  alcohol.  Barium 
and  calcium  palmitates  are  slightly  soluble  in  alcohol. 

d. — In  qualitative  reactions  palmitic  acid  does  not  sensibly 
differ  from  stearic  acid.  Its  distinction  from  stearic  acid  re- 
quires quantitative  work. 

e. — Separations  of  palmitic  acid  are  made  with  stearic  acid,  or, 
if  this  be  absent,  by  the  same  methods  given  for  stearic  acid  sep- 
aration (Stearic  Acid,  e). 

1  This  synonym  is  used  by  some  French  chemists. 


VARIOUS  ACIDS.  245 

y. — Quantitative  determinations  of  palmitic  acid  alone  are 
done  by  the  methods  given  for  Stearic  acid.  When  in  mixture 
with  stearic  acid,  methods  of  indirect  determination  are  resorted 
to,  as  given  under  Fatty  Acids,  Quantitative  Estimation  of,  (5) 
and  (7). 

g. — Palmitic  acid  enters  into  the  stearic  acid  known  in  com- 
merce and  in  candle  manufacture  as  "  Stearin,"  and  into  "  Oleo- 
margarin."  See  under  these  heads  (Index). 

MYRISTIC  ACID,  C14H28O2. — The  fourteen-carbon  member  of 
the  CnH2nO2  series  of  fat  acids.  Closely  resembles  Laurie  acid. 
A  solid,  melting  at  53.8°  C.,  at  which  temperature  the  liquid  has 
sp.  gr.  0.8622.  It  is  insoluble  in  water,  sparingly  soluble  in 
cold  alcohol  and  in  ether. 

LAURIC  ACID. — The  C-^IL^Og  acid  obtained  from  fats  is  a 
solid,  fusible  at  48.6°  C.,  and  of  sp.  gr.  0.883  at  20°  C.  It  crys- 
tallizes from  alcohol  in  needles.  It  does  not  vaporize,  alone 
and  under  ordinary  pressure,  without  being  mostly  decomposed, 
but  distils  with  steam.  In  large  quantities  of  boiling  water 
sensible  traces  are  dissolved. 

CAPRIC  ACID,  C10H20O2. — The  capric  acid  obtained  from  fats 
is  solid  at  ordinary  temperatures,  forming  small  tabular  crystals, 
melting  at  31.3°  to  31.4°  C.,  boiling  at  268°-270°  C.,  and  of  sp. 
gr.  0.93  at  37°  C.  It  is  soluble  in  about  1000  parts  of  water ; 
its  calcium  salt,  very  slightly  soluble  in  water. 

CAPRYLIC  ACID,  C8H16O2. — The  caprylic  acid  obtained  from 
fats  congeals  at  12°  C.  to  a  crystalline  mass,  melting  at  16.5°  C. 
Boils  at  236°-237°  C.  At  20°  C.  has  sp.  gr.  0.914.  Of  a  sweet 
taste.  Soluble  in  400  parts  of  water.  The  calcium  salt  dissolves 
in  200  parts  of  water. 

CAPROIC  ACID,  C6II12O2.  Isobutyl-acetic  acid.  Found  as 
a  glyceride  in  fats. — Congeals  at  —  18°  C.,  boils  at  199.7°  C.,  is 
scarcely  at  all  soluble  in  water.  At  20°  C.,  sp.gr.  0.925.  Of 
a  sweetish  taste.  The  calcium  salt  dissolves  in  37  parts  of 
water. 

FATTY  SERIES  OF  ACIDS,  CnH2n_2O2.  Oleic  acid  series.  The 
following  members  of  this  and  other  immediately  related  series 
are  found  in  fats  : 


246  FA  TS  AND   OILS. 

Oleic  Acid  .......  C18H3402  =  C17H33.CO2H. 


SERIES  CnH2n_2O3  : 
Ricinoleic  Acid.  .  .  C18H34O3. 

SERIES  Onll^.^  : 
Linoleic  Acid....  C16H28O2  =  C15H27.C02H. 

OLEIC  ACID,  C18H34O2  =  282.—  The  members  of  the  fatty 
series  CnH2n_2O2  contain  two  atoms  of  hydrogen  less  than  cor- 
responding members  of  the  fatty  series  CnH2nO2  ,  and  by  action 
of  reducing  agents  the  former  are  in  general  convertible  into  the 
latter.  The  normal  glyceride  of  oleic  acid,  olein,  C3H5(C18H33O2)3 
=:  884,  is  found  in  greater  or  smaller  proportion  in  most  vegeta- 
ble and  animal  fats,  and  in  non-drying  oik. 

a.  —  Pure  oleic  acid  is  a  colorless  oil,  congealing  at  4°  C.,  melt- 
ing at  14°  C.,  at  which  temperature  the  liquid  has  sp.  gr.  0.898. 
Under  ordinary  pressure  it  does  not  distil  alone  undecomposed, 
but  is  carried  over  with  superheated  steam  at  about  250°  0.  — 
The  triglyceride,  olein,  is  a  liquid  which  congeals  at  low  atmos- 
pheric temperatures,  and  in  vacuum  distils  slowly  without  de- 
composition. 

b.  —  Oleic  acid  is  a  bland,  tasteless,  when  pure  nearly  or  quite 
odorless  liquid,  indifferent  in  physiological  action. 

c.  —  Oleic  acid  is  insoluble  in  water,  soluble  in  alcohol  not 
very  dilute,  and  separated  from  the  solid  fat  acids  by  its  greater 
solubility  in  a  mixture  of  acetic  acid  and  alcohol.     It  is  soluble 
in  chloroform,  benzol,  petroleum  benzin,  and  in  the  fixed  oils.  — 
The  triglyceride,  olein,  is  somewhat  soluble  in  absolute  alcohol, 
in  fact  much  more  so  than  are  stearin  and  palmitin,  but    is  inso- 
luble in  dilute  alcohol.  —  Pure  oleic  acid  is  neutral  to  litmus-pa- 
per, but  it  gives  the  acid  reaction  with  phenol-phthalein,  decolor- 
ing the  alkaline  mixture  of  this  indicator  at  formation  of  normal 
alkali  oleates.  —  By  exposure  to  air  for   a  short  time  oleic  acid 
suffers  such  changes  as  impart  to  it  an  acid  reaction,  and  it  soon 
becomes  rancid  and  of  a  yellowish  color.  —  The  alkali  oleates  are 
soluble  in  water,  the  solution  becoming  somewhat  turbid  by  de- 
composition when  diluted  with  water,  though  bearing  dilution 
better  than  stearate  or  palmitate.     The  oleates  of  non-alkali  me- 
tals are  insoluble  in  water,  but  more  or  less  freely  soluble  in  al- 
cohol, and  in  some  instances  (including  the  lead  salt)  soluble  in 


O LEI C  ACID.  247 

ether.  The  silver  oleate  is  not  soluble  in  ether. — The  alkali 
oleates  are  precipitated  from  their  aqueous  solutions  by  sodium 
chloride,  and  to  some  extent  by  excess  of  alkalies.  Sodium  oleate 
is  soluble  in  10  parts  of  water  at  12°  C.,  in  20.6  parts  of  alcohol 
of  0.821  applied  at  13°  C.,  or  in  100  parts  of  boiling  ether.  From 
absolute  alcohol  it  is  crystallizable.  Potassium  oleate,  in  ordi- 
nary moist  condition,  is  soft  or  gelatinous,  and  is  much  more  so- 
luble in  water  or  alcohol  or  ether  than  is  the  sodium  salt.  Ba- 
rium oleate  is  insoluble  in  water,  and  but  very  slightly  soluble  in 
alcohol.  Magnesium-alkali  oleate  possesses  a  capacity  of  slight 
and  transient  foaming  in  aqueous  solution,  perhaps  due  to  a  tardy 
precipitation,  and  distinguishing  it  from  calcium  oleate  in  the 
soap  test  of  hard  waters. 

d.— Oleic  acid  is  characterized  by  its  consistence  as  a  liquid 
non-volatile  fatty  body,  and  by  the  action  of  oxidizing  agents 
upon  it.  Nitric  acid  with  metallic  copper,  fuming  nitric  acid, 
mercury  nitrates,  or  other  form  of  nitrous  acid,  in  digestion  with 
oleic  acid,  produces  its  isomer  elaidic  acid,  as  in  digestion  with 
olein  it  forms  elaidin,  glyceride  of  elaidic  acid.  Elaidic  acid  is  a 
solid,  and  its  formation  is  indicated  first  by  a  soft  waxy,  and 
finally  by  a  resinous  consistence.  Elaidic  acid  dissolves  in  alco- 
hol, from  which  it  crystallizes  in  tabular  forms,  melting  at  45°  C. 
—  Bromine  acts  readily,  and  iodine  or  chlorine  quite  easily,  on 
oleic  acid,  producing  dibrom-stearic  acid,  an  addition  product  of 
oleic  acid,  C17H33Br2 .  CO2H,  on  the  type  of  the  CnII2nO2  series. 
To  7  parts  of  the  oleic  acid  4  parts  of  bromine  are  added,  drop 
by  drop,  stirring  after  each  addition.  The  product  is  yellowish, 
of  an  oily  consistence.  To  form  the  di-iod-stearic  acid,  molecular 
proportions  of  the  oleic  acid  and  of  the  iodine  are  taken,  each 
being  dissolved  in  alcohol,  when  the  iodine  solution  is  gradually 
added,  this  being  the  reaction  of  Hiibl's  estimation,  giving  the 
iodine  number. 

e. — Separations. — In  manufacture  oleic  acid  is  separated  from 
the  solid  fat  acids  by  filtration  under  pressure  at  low  tempera- 
tures above  the  congealing  point  of  the  oleic  acid. 

For  methods  of  separation  from  the  solid  fat  acids  by  sol- 
vents, etc.,  see  Stearic  acid,  e.  Directions  for  separation  (pro- 
duction) from  olein  by  saponification  are  essentially  those  given 
under  Hehner's  method. 

f. — Quantitative. — Oleic  acid  is  estimated  volumetrically  by 
standard  solution  of  potassa  or  soda,  using  phenol-phthalein  as 
an  indicator.  Each  c.c.  of  normal  solution  of  alkali  represents 


248  FATS  AND   OILS. 

0.282  gram  of  oleic  acid.  Taking  2.82  grams  of  material,  each 
c.c.  of  decinormal  solution  of  alkali  counts  1  per  cent,  of  oleic 
acid.  Taking  14.1  gram  of  material,  c.c.  of  normal  solution  of 
alkali  X !  2  =  per  cent,  oleic  acid.  Gravimetric  estimation  of  free 
oleic  acid  is  effected  by  adding  to  the  free  acid,  in  a  layer  over 
an  aqueous  liquid,  a  weighed  portion  of  recently  fused  beeswax 
or  paraffin,  heating  to  melt  the  solid,  and  when  cold  detaching 
the  oily  mass,  drying  in  a  tared  capsule,  and  weighing,  when  the 
weight  of  the  wax  is  subtracted.  Also  free  oleic  acid,  dissolved 
in  ether,  may  be  freed  from  the  latter  by  evaporation  in  a  tared 
beaker  or  flask,  avoiding  oxidation  by  exposure  to  the  air,  and 
the  weight  of  the  oleic  acid  may  be  obtained. 

g. — The  U.  S.  Ph.  gives  the  following  specifications  for  oJeic 
acid  :  "  At  14°  C.  (57°  F.)  it  becomes  semi-solid,  and  remains  eo 
until  cooled  to  4°  C.  (39°  F.),  at  which  temperature  it  becomes  a 
whitish  mass  of  crystals.  At  a  gentle  heat  the  acid  is  completely 
saponified  by  carbonate  of  potassium.  If  the  resulting  soap  be 
dissolved  in  water  and  exactly  neutralized  with  acetic  acid,  the 
liquid  will  form  a  white  precipitate  with  test  solution  of  acetate 
of  lead.  This  precipitate,  after  being  twice  washed  with  boiling 
water  [drained  and  dried],  should  be  almost  entirely  soluble  in 
ether  (absence  of  more  than  traces  of  palmitic  and  stearic  acids). 
Equal  volumes  of  the  acid  and  alcohol,  heated  to  25°  C.  (77°  F.), 
should  give  a  clear  solution,  without  separating  oily  drops  upon 
the  surface  (fixed  oils)." — The  specifications  of  the  Br.  Ph.  are 
as  follows  :  "  A  straw-colored  liquid,  nearly  odorless  and  tasteless, 
and  with  not  more  than  a  very  faint  acid  reaction.  Unduly  ex- 
posed to  air  it  becomes  brown  and  decidedly  acid.  Specific 
gravity  0.860  to  0.899.  At  40°  to  41°  F.  (4.5°  to  5.0°  C.)  it  be- 
comes semi-solid,  melting  again  at  56°  to  60°  F.  (13.3°  to  15.5°  C.) 
It  should  be  completely  saponified  when  warmed  with  carbonate 
of  potassium,  and  an  aqueous  solution  of  this  salt  neutralized  by 
acetic  acid  and  treated  with  acetate  of  lead  should  yield  a  preci- 
pitate which,  after  washing  with  boiling  water,  is  almost  entirely 
soluble  in  ether." 

RICINOLEIC  ACID,  C18H34O3=298. — The  fat  acid  constituting, 
in  its  normal  glyceride,  the  principal  part  of  castor  oil.  In  com- 
position an  oxy-oleic  acid  of  the  proportions  CnH2n_2O3. 

a. — A  thick  oil,  of  sp.  gr.  0.940  at  15°  C.,  congealing  at— 6° 
to  —10°  C.,  and  does  not  vaporize  undecomposed.  The  lead  salt 
melts  at  100°  C. 

b. — The  glyceride,  as  obtained  in  castor  oil,  is  odorless,  with  a 


LINOLEIC  ACID.—HYPOGAIC  ACID.  249 

mild  taste  and  slightly  acrid  after-taste,  and  exerting  a  cathartic 
effect. 

c. — Ricinoleic  acid  is  insoluble  in  water ;  soluble  in  all  pro- 
portions in  alcohol  and  in  ether.  The  lead  salt  is  soluble  in 
ether.  Castor  oil  is  soluble,  at  15°  C.,  in  2  parts  of  90$  alcohol  or 
4  parts  of  84$  alcohol.  It  is  but  slightly  soluble  in  petroleum 
benzin,  paraffin  oil,  or  kerosene,  though  it  takes  up  about  its  own 
volume  of  petroleum  benzin. 

d. — Ricinoleic  acid  is  but  very  slightly  oxidized  by  exposure 
to  air.  Treated  with  bromine  it  takes  two  atoms  of  bromine  in 
the  molecule  of  the  acid,  forming  C18H34Br2O3 ,  corresponding 
to  the  reaction  of  oleic  acid.  In  the  elaidin  reaction,  by  action  of 
nitric  acid,  ricinelaidic  acid  is  formed,  isomeric  with  ricinoleic 
acid,  and  fusible  at  50°  C. 

LINOLEIC  ACID,  Ci6H28O2— 252. — The  only  well-known  mem- 
ber of  the  series  of  fat  acids  OnH2n_4O2.  In  the  normal  glyce- 
ride  forms  the  principal  portion  of  linseed  oil,  representative  of 
the  drying  oils.  In  oxidation,  or  "  drying,"  it  forms  addition 
products,  such  as  C16H28Br4O2 ,  corresponding  in  composition  to 
CnH2nO2.  Therefore  .in  reaction  with  oxidizing  agents  it  has 
twice  the  saturating  power  per  molecule  possessed  by  oleic  acid. 

a. — Linoleic  acid  is  a  permanent  liquid  of  a  pale  yellow  color 
and  sp.  gr.  0.9206  at  14°  C.  The  glyceride,  as  obtained  in  linseed 
oil,  congeals  at  —16°  C.  (GussEBow),  —27°  C.  (AECHBUTT  and  AL- 
LEN), and  melts  at  16°  to  20°  C.  (GLASSNEE). 

b. — Linseed  oil  has  a  characteristic  odor  and  taste. 

G. — Insoluble  in  water,  readily  soluble  in  alcohol  and  in  ether. 
Of  a  feeble  acid  reaction,  and  capable  of  neutralizing  alkalies  to 
phenol-phthalein  and  other  indicators. 

The  barium  and  calcium  salts  dissolve  in  hot  alcohol.  Ether 
dissolves  the  linoleates  of  lead,  zinc,  copper,  and  calcium. 

d. — Linoleic  acid  is  easily  oxidized  by  exposure  to  the  air. 
In  thin  layers  in  a  few  days  it  forms  a  solid,  resin-like  body 
known  as  Oxylinoleic  acid,  and  afterward  takes  on  the  character 
of  a  neutral  body,  insoluble  in  ether,  and  sometimes  termed 
Linoxyn. 

HYPOGAIC  ACID,  C16H30O2. — A  white  solid,  crystallizing  in 
needles,  melting  at  33°  C.,  not  readily  vaporizing  in  ordinary 
conditions  without  decomposition.  By  exposure  to  air  soon  be- 


250  FATS  AND   OILS. 

corned  rancid,  acquiring  a  brown  color,  and  giving  origin  to  vola- 
tile acids.  In  the  elaidin  test  it  is  changed  to  its  isomer  gaidic 
acid,  fusible  at  39°  C. 

PHYSETOLEIC  ACID,  isomeric  with  Hypogaic  acid,  C16H30O2, 
melts  at  30°  C.,  and  is  not  affected  by  the  elaidin  test. 

FAT  ACIDS,  QUANTITATIVE  DETERMINATIONS  OF. — Besides  the 
methods  of  volumetric  and  gravimetric  estimation  of  separate  fat 
acids,  or  of  total  fat  acids  in  terms  of  stearic  acid,  by  equivalence 
of  saturation,  certain  special  determinations  have  been  made, 
upon  stated  authorities,  as  indices  of  composition,  related  to  as- 
certained limits,  representing  values  for  given  uses. 

(1)  The  number  of  parts  of  insoluble  fat  acids  obtainable 
from  100  parts  of  clear  neutral  fat  (HEHNER'S  number). 

(2)  The  number  of  c.c.  of  decinormal  alkali  solution  saturated 
by  the  volatile  fat  acids  distilled  from  2. 5  grams  of  the  fat 
(REICHERT'S  number). 

(3)  The  number  of  milligrams   (thousandths)   of  potassium 
hydrate  saturated  by  saponifying  1  gram  (one  part)  of  the  fat 
(KOTTSTORFER'S  number).     The  sapoimication  number. 

The  methods  above  named  have  been  devised  to  distinguish 
butter  from  its  substitutes. 

(4)  The  percentage  of  iodine  which  the  oleins  of  the  fat  will 
take  into  combination  by  a  defined  procedure  (HUBL'S  iodine 
numberX 

(5)  The  molecular  weight,  as  obtained  by  acidimetry.     (The 
quantity  saturated  by  1000  c.c.  normal  solution  of  alkali.)     For 
mixtures  of  palmitic  and  stearic  acids. 

(6)  The  specific  gravity,  as  a  limited  indication. 

(7)  The  melting  and  congealing  points. 

(8)  Calculation  of  constituent  Fat  Acids  and  Neutral  Fats. 

(1)  Estimation  of  the  insoluble  fat  acids  :  HEHNER'S  Method.1 
— To  obtain  the  butter  fat  from  butter  melt  a  portion  on  the 
water-bath,  leave  the  liquid  to  settle  while  melted,  decant  the 
<?lear  liquid  only  upon  a  dried  filter  in  a  hot  funnel,  and  take 
the  filtrate.  It  must  be  perfectly  clear  and  not  lose  weight  on 

J0.  HEHNER,  1877:  Zeitsch.  anal.  Chem.,  16,  145.  HEHNER  and  ANGELL, 
1877:  "Butter,  its  Analysis  and  Adulterations,"  London,  second  edition.  MU- 
TER, 1876:  Analyst,  i,  7.  DUPRE,  1876:  Phar.  Jour.  Trans.,  ]>],  7,  131. 
JONES,  1877:  Analyst,  2,  20.  FLEISCHMANN  and  VIETH.  1878:  Zeitsch.  anal. 
Chem.,  17,  287.  Manipulation  at  the  Depart,  of  Agriculture,  Washington, 
REPORT  DEPT.  AGR.,  1884,  Prof.  WILEY,  Chemist,  p.  60.  Further,  see  citations 
under  Butter  Fat. 


DE  TERMINA  TION  OF  FAT  A  CIDS.  2  5 1 

the  water-bath.  Keep  in  a  light  beaker,  and  take  out  for  an 
analysis  from  3  to  4  grams  of  the  clear  fat  into  an  evaporating- 
dish  of  about  5  inches  (13  centimeters)  diameter,  using  a  glass 
rod  to  be  left  in  the  evaporating-dish,  and  weighing  tli^e  beaker 
before  and  after  the  removal  to  obtain  the  exact  weight  of  fat 
taken.  Add  50  c.c.  of  alcohol  of  about  85$,  and  1  to  2  grams  of 
pure  (alcoholic)  potassium  hydrate,  and  warm  and  stir  the  mix- 
ture until  a  clear  solution  is  obtained.  After  five  minutes'  fur- 
ther warm  digestion  add  a  few  drops  of  distilled  water,  and  if  a 
turbidity  is  caused  continue  the  digestion  until  the  addition  of 
water  produces  no  turbidity.  If  this  satisfactory  saponification  is 
not  attained  the  failure  is  probably  due  to  a  too  great  dilution  of 
the  potash  with  alcohol,  and  the  operation  is  to  be  commenced 
anew.  If  the  alcohol  be  too  strong,  saponification  is  prevented. 
The  clear  saponified  solution  is  now  evaporated  over  the  water- 
bath  to  a  syrupy  consistence,  and  the  residue  dissolved  in  100  to 
150  c.c.  of  water.  To  the  clear  liquid  add  diluted  sulphuric  or 
hydrochloric  acid  to  a  strongly  acid  reaction.  The  creamy  sepa- 
rate of  the  insoluble  fat  acids  rises  for  the  most  part  to  the  sur- 
face. Heat  of  a  bath  of  water  below  boiling  is  now  applied  to 
melt  the  precipitate,  and  continued  for  half  an  hour  and  until 
the  layer  of  fat  acids  above  is  perfectly  clear  and  the  aqueous 
liquid  below  is  nearly  clear.  Meantime  a  filter  of  4  to  5  inches 
(10  to  13  centimeters)  diameter,  of  the  closest  filter-paper  (Swe- 
dish), is  dried  in  the  water-box.  The  filter  should  be  close 
enough  to  transmit  hot  water  only  by  drops.  A  small  beaker 
is  weighed,  also  a  filter  weighing-tube  and  this  tube  with  the 
filter,  to  give  the  weight  of  the  latter. 

The  weighed  filter  is  placed  in  a  funnel  wetted  and  half -filled 
with  water.  The  watery  liquid  and  melted  fat  are  then  poured 
from-  the  dish  upon  the  filter,  which  is  not  to  be  at  any  time 
more  than  two- thirds  filled ;  the  dish  and  rod  are  rinsed  with 
boiling  water,  and  washing  with  boiling  water  is  to  be  continued 
until  the  washings  cease  to  redden  liimus-paper,  about  f  liter 
(700  to  1000  c.c.)  of  filtrate  being  usually  obtained.1  (The  rins- 
ing of  the  dish  seldom  leaves  behind  more  than  a  milligram  of 
fat,  but  this  is  saved  by  taking  it  up  with  a  little  ether  and  the 
solution  added  to  the  fat  acids  in  the  beaker  afterward.)  The 

1  FLETSCHMANN  and  VIETH  (1878)  advise  care  to  avoid  imperfect  solution  of 
lauric  acid  (abounding  in  cocoanut  oil),  washing  until  5  c.c.  of  the  filtrate 
ceases  to  change  the  color  of  one  drop  of  litmus  tincture  added  thereto.  E. 
WALLER  and  his  associates  (1886:  Report  N.  Y.  State  Dairy  Commissioner) 
wash  with  six  or  seven  instalments  of  hot  water  (about  100  c.c.  each),  rinsing 
off  between  each  with  about  25  c.c.  of  cold  water. 


252  FATS  AND   OILS. 

drained  funnel  is  set  well  down  in  a  beaker  of  cold  water,  and 
when  the  fat  acids  have  hardened  the  filter  is  detached,  drained, 
and  placed  in  the  weighed  beaker. '  This  is  heated  on  the  water- 
bath  to  a  (nearly)  constant  weight.  Weigh  after  about  two  hours' 
drying,  and  after  a  half-hour's  further  drying  weigh  again.  If 
any  drops  of  water  collect  below  the  fat  add  a  drop  or  two  of 
alcohol.  In  this  drying  there  may  be  slight  increase  by  oxida- 
tion of  oleic  acid,  and  slight  decrease  by  vaporization  of  fat  acids. 
If  the  filter  have  been  close  enough  no  fat  globules  will  have 
passed,  and  none  will  be  revealed  by  microscopic  examination  of 
the  filtrate. 

The  weight  of  the  beaker  and  contents,  minus  the  weights  or 
tares  of  the  beaker  and  the  filter,  leaves  the  weight  of  the  fat 
acids,  which  is  to  be  divided  by  the  weight  of  purified  fat  taken, 
to  obtain  the  proportion  •(  X  100  =  $)  of  insoluble  fat  acids. 

If  87.5  be  accepted  as  the  full  per  cent,  of  insoluble  fat  acids 
in  butter,  and  95.5  as  the  per  cent,  of  insoluble  fat  acids  in  "  meat 
fats,"  then  95  5  —  87.5  =  8,  and  8  :  found  percentage  minus 
87.5  ::  100  :  a?  =  per  cent,  of  "  meat  fats"  present  in  the  clear 
fat  examined.  For  the  calculation  of  percentage  in  entire  but- 
ter see  under  Butter,  Interpretation  of  Results. 

DALICAN  modifies  Hehner's  process  by  taking  10  grams  of  the 
clear  butter  fat  in  a  flask  of  250  to  300  c.c.  capacity,  and  adding 
80  c.c.  of  85$  alcohol,  and  6  grams  of  sodium  hydrate  dissolved 
in  6  to  8  c.c.  water,  when  by  30  to  40  minutes  of  warming  and 
stirring  the  saponification  is  ended.  The  alcohol  is  evaporated 
off,  150  c.c.  of  water  added,  and  25  c.c.  of  hydrochloric  acid 
diluted  with  four  parts  of  water  are  added  in  small  portions  at  a 
time,  rotating  the  flask  after  each  addition.  The  mixture  is  now 
heated  over  the  water-bath  for  25  to  30  minutes,  until  the  fat 
layer  separates  with  perfect  clearness  and  white  points  are  no 
longer  seen.  The  flask  is  set  aside  for  30  minutes,  and  then 
cooled  with  water.  After  two  hours  the  fat  layer  is  broken 
with  a  glass  rod,  the  water  poured  on  a  wetted  filter,  about  250 
c.c.  of  boiling  water  added  in  two  portions  to  the  flask,  shaking 
after  adding  the  first  portion.  The  flask  is  then  set  aside  40 
minutes,  cooled  by  immersion  in  water,  and  the  water  decanted 
on  the  filter  as  before.  This  washing  by  decantation,  as  above, 
is  repeated  until  the  decanted  liquid  ceases  to  redden  litmus- 
paper  on  20  minutes'  contact,  8  or  10  washings  being  necessary. 

1  "The  insoluble  acids  are  brought  into  a  tared  dish,  any  in  the  filter  or 
flask  being  dissolved  in  ether,  dried  at  100°  C.  with  stirring  with  absolute  alco- 
hol to  remove  water,  and  weighed."  H.  W.  WILEY,  Chemist  Dept.  Agricul- 
ture, Washington,  Report  of  1884. 


DE  TERMINA  TION  OF  FAT  A  CTDS.  2  5  3 

The  insoluble  fat  acids  are  finally  gathered  in  a  tared  porcelain 
capsule  or  evaporating-dish,  the  flask  being  washed  with  hot 
water,  and  all  washings  passed  through  the  filter.  The  filter 
must  be  kept  wet,  and  the  slight  portion  of  fat  acids  upon  it  can 
easily  be  detached.  The  drying  is  done  at  100°  to  110°  C.,  at 
first  for  an  hour,  and  a  second  weight  is  taken  in  15  or  20 
minutes.  For  results  with  vegetable  and  animal  fats  see  tables 
following  ;  also  Butter  Fat. 

(2)  REICHERT'S  method1  embraces  the  estimation  of  the  vola- 
tile fat  acids,  separated  by  distillation.  "  Reichert's  number"  is 
the  number  of  c  c.  of  decinormal  solution  of  alkali  taken  to  neu- 
tralize the  distilled  fat  acids  from  2.5  grams  of  fat.  Sometimes, 
however,  results  are  specified  for  5  grams  or  for  10  grams  of  the  fat. 

Of  the  clear  filtered  fat  2.5  grams  are  taken  in  an  Erlen- 
meyer's  flask  of  about  150  c.c.  capacity,  with  1  gram  potassium 
"hydrate  and  20  c.c.  of  80$  alcohol,  and  the  whole  digested  on  the 
water-bath,  with  shaking  by  circular  motion  until  saponification 
is  complete  and  the  alcohol  is  all  removed.  Now  50  c.c.  of 
water  are  added,  then  20  c.c.  of  diluted  (1  to  10)  sulphuric  acid, 
and  the  mixture  distilled.  To  avoid  bumping  a  slight  stream  of 
air  may  be  introduced.  The  distillate  is  received  in  a  50  c.c. 
flask,  into  which  is  set  a  funnel  carrying  a  wetted  filter,  receiving 
the  distillate,  so  that  any  insoluble  fat  acid  otherwise  possible  in 
the  distillate  may  be  rejected.  The  first  10  or  20  c.c.  of  distillate 
are  returned  to  the  flask  ;  then  50  c.c.  are  distilled.  The  volume 
of  the  distilled  liquid  should  always  bear  the  same  proportion  to 
that  of  the  distillate.  This  distillate  is  charged  with  a  few  drops 
of  phenol-phthalein  solution,  and  titrated  with  the  decinormal 
solution  of  alkali,  until  the  color  of  the  alkali  reaction  becomes 
constant.  The  required  number  of  c.c.  (2.5  grams  of  fat  having 
been  taken)  is  Reichert's  number. 

MEISSL'S  modification  of  Reichert's  process2  undertakes  a 
more  complete  distillation  of  the  volatile  fat  acids,  and  the  use  of 
weaker  alcohol  in  saponifl  cation  to  avoid  etherizing  the  acids,  as 
follows  :  5  grams  of  the  clear  filtered  fat  are  treated  in  a  flask  of 
200  c.c.  capacity  with  2  grams  of  solid  potash  and  50  c  c.  of 
alcohol  (free  from  acidity  or  aldehyde),  over  the  water-bath, 


1E.  REICHERT,  1879:  Zeitsch.  anal.  Chem.,  18,  68;  Jour.  Chem.  Soc.,  36, 
406.  ALLEN,  1885:  Analyst,  10,  103.  R.  W.  MOORE,  1885:  Jour.  Am.  Chem. 
Soc.,  7,  188;  Analyst,  10,  224;  Am.  Chem.  Jour.,  6,  417:  Chem.  News,  50, 
268;  Jour.  Chem.  Soc.,  48,  300,  1014.  E.  REICHAEDT,  1884:  Zeitsch.  anal. 
Chem.,  23,  565;  Jour.  Chem.  Soc.,  46,  1219. 

2E.  MEISSL,  1880:  Bied.  Cent.,  1880,  471;  Jour.  Chem.  Soc  ,  38,  828. 


254  "FATS  AND   OILS. 

with  stirring,  until  saponified  perfectly.  The  alcohol  is  evapo- 
rated, and  the  thick  soap  is  dissolved  in  100  c.c.  of  water,  pre- 
cipitated with  40  c.c.  of  diluted  (1  to  10)  sulphuric  acid,  and,  after 
the  addition  of  a  few  pieces  of  pumice-stone,  distilled  with  use  of 
a  Liebig's  condenser.  Of  distillate  110  c.c.  are  received  in  a  flask 
marked  at  this  capacity,  this  quantity  being  obtained  in  about  an 
hour.  The  distillate  is  filtered  into  a  flask  marked  at  100  c.c., 
and  this  volume  of  the  filtrate  is  titrated,  after  addition  of  phe- 
nol-phthalein  or  litmus,  with  decinormal  solution  of  alkali.  The 
number  of  c.c.  required  is  increased  by  its  one-tenth,  and  for 
Reichert's  number  (on  2.5  of  fat)  the  result  of  this  operation  is 
divided  by  two.  To  exclude  all  interferences  a  control  analysis 
without  fat  may  be  conducted  parallel  with  the  assay. 

The  Reichert's  numbers  of  fats  are  given  under  Butter  Fat. 

(3)  Kottstorfer1  s  method  l  Determination  of  the  number  of 
milligrams  of  potassium  hydroxide  necessary  to  saponify  1  gram 
of  the  fat — the  "  Yerseif ungszahl,"  or  saponification  number. 
The  operation  requires  (1)  solution  of  hydrochloric  acid,  and  (2) 
alcoholic  solution  of  potassa,  both  of  about  half-normal  strength. 
Also  (3)  a  decinormal  solution  of  alkali,  exactly  standardized. 
The  potassa  solution  is  made  of  caustic  potassa  purified  by  alco- 
hol, dissolved  in  the  least  sufficient  proportion  of  water  and  di- 
luted to  standard  with  alcohol  free  from  fusel  oil.  It  may  be 
prepared  by  filtration  through  'animal  charcoal.  If  the  alcohol 
be  pure  a  solution  of  the  designated  strength  will  not  become 
darker  than  yellowish. 

Of  the  purified  fat  1  to  2  grams  are  digested  in  a  covered 
beaker  or  flask  of  about  70  c.c.  capacity,  with  just  25  c.c.  of 
the  alcoholic  potassa  solution,  on  the  water-bath,  at  near  boiling 
of  the  liquid,  stirring  with  a  glass  rod,  to  perfect  saponification. 
It  is  believed  to  be  necessary  to  take  precautions  against  the 
escape  of  ethyl  butyrate. 

One  c.c.  of  phenol-phthalein  solution  is  added,  and  the  liquid 
titrated  with  the  standard  hydrochloric  acid  to  the  neutral  point. 
Another  25  c.c.  of  the  potash  solution  alone  is  titrated  with  the 
hydrochloric  acid  solution,  and  the  latter  titrated  with  the  deci- 
normal alkali.  The  number  of  c.c.  of  the  standard  alkali  taken 
for  the  1  gram  of  fat,  minus  the  hydrochloric  acid  in  the  titra- 
tion,  converted,  according  to  the  comparisons  made,  into  milli- 

1  J.  KOTTSTORFER,  1879:  Zeitsch.  anal.  Chem.,  18,  199,  431;  Jour.  Chem. 
Soc.,  36,  983,  1069;  Analyst,  4,  106.  MOORE,  1885:  Jour.  Amer.  Chem.  Soc., 
7,  188;  Analyst,  10,  224;  Chem.  News,  50,  268;  Am.  Chem.  Jour.,  6,  417; 
Jour.  Chem.  tioc.,  48,  300,  1014. 


DETERMINATION  OF  FAT  ACIDS.  255 

grams  of  potassium  hydroxide,  gives  the  saponification  number 
sought. 

The  details  are  carried  out  upon  fats  of  butter  and  its 
substitutes  by  Prof.  WILEY  (1884)  as  follows :  The  dried  and 
filtered  butter-fat  is  weighed  in  a  small  beaker  with  a  2  c.c. 
pipette.  Five  stout  half-pint  beer-bottles  of  clear  glass,  with 
rubber  stoppers  secured  by  a  spring,  are  provided.  Three 
portions,  of  2  c.c.  each,  of  the  fat  melted  at  about  35°  C.  are 
introduced  severally  into  three  of  the  bottles,  weighing  the 
beaker  and  pipette  after  each  addition,  and  noting  the  exact 
weight  of  fat  taken  in  each  of  the  three  bottles.  Of  the  alco- 
holic potash  solution  just  25  c.c.  is  now  run  into  each  of  the  five 
bottles.  The  bottles  are  stoppered  and  placed  on  the  same  steam 
or- water-bath,  and  shaken  every  five  minutes  until  the  fat  is  sa- 
ponified. Then  the  bottles  are  cooled,  opened,  and  1  c.c.  phenol- 
phthalein  solution  added  to  each.  Each  of  the  five  portions  is 
now  titrated  with  the  half -normal  hydrochloric  acid  to  the  neu- 
tral point.  The  two  blanks  give  an  average  for  the  strength  of 
the  alcoholic  potash,  and  the  three  portions  of  fats  give  an  ave- 
rage for  the  amount  of  potash  neutralized  in  saponification. — 
That  is,  the  mean  number  of  c.c.  of  hydrochloric  acid  for  one  of 
the  two  blank  portions,  minus  the  mean  of  c.c.  of  the  same  acid 
calculated  for  1  gram  of  fat  in  one  of  the  three  fat-portions,  equals 
the  no.  c.c.  of  the  hydrochloric  acid  neutralized  by  the  total  fat 
acids  in  1  gram  of  the  fat.  This  last  no.  of  c.c.  of  hydrochloric 
acid  is  to  be  titrated  with  the  exactly  standardized  decinormal  al- 
kali, and  the  required  no.  of  c.c.  of  the  latter  is  multiplied  by 
5.6  to  obtain  the  milligrams  KOH  for  the  fat  acids  of  1  gram 
of  fat. 

Kottstorfer's  Number,  the  milligrams  of  KOH  to  saponify  1 
gram  of  fat,  is  to  be  distinguished  from  the  "  Saturation-Equi- 
valent "  of  fats.  The  latter  term  is  defined  as  the  number  of 
milligrams  of  fat  saponifiable  by  1  c.c.  of  normal  alkali  solution. 
For  the  triglycerides  it  is  the  third  of  their  molecular  weight ; 
or  it  is  the  hydrogen-equivalent  number  of  the  fat.  56000 
-T-  Kottstorfer's  number  =  "  saturation-equivalent  "  ;  and  56000 
-r-  "  saturation -equivalent  "  =  Kottstorfer's  number. 

PEKKINS  1  combines  the  methods  of  Hehner,  Reichert,  and 
Kottstorfer,  as  follows  :  Of  the  clear  fat  1  to  2  grams  is  saponified  ; 
an  excess  of  a  cold-saturated  solution  of  oxalic  acid  is  added,  and 
the  fat  acids  separated  in  the  cold,  and  then  washed  on  the  filter 
with  hot  water.  The  filtrate  is  made  up  to  200  c.c.,  and  distilled 

1  F.  P.  PERKINS,  1878:  Analyst,  3,  241;  Zeitsch.  anal.  Chem.,  19,  237. 


256 


FATS  AND   OILS. 


to  give  100  c.c.  of  distillate  (according  to  Reichert),  this  being 
titrated  with  alkali  and  the  result  stated  in  milligrams  of  potas- 
sium hydroxide  to  saturate  the  volatile  acids  from  1  gram  of  pu- 
rified fat.  The  insoluble  fat  acids,  as  washed,  are  dissolved  in 
100  c.c.  of  hot  alcohol,  and  this  solution,  or  an  aliquot  part  of  it, 
titrated  with  decinormal  alkali,  calculating  the  result  into  milli- 
grams of  potassium  hydroxide  for  the  insoluble  fat  acids  of  1 
gram  of  fat.  The  former  number  plus  the  latter  number  gives 
the  milligrams  of  potassium  hydroxide  to  saturate  all  the  fat 
acids  of  the  1  gram  of  purified  fat. 


Percentages  of  Insoluble  Fat  Acids.     Hehner's  Numbers. 


Olein. 

Palmitiii 

Stearin 

Eutyrin 

Oleomargarin. . 

Cotton- seed  oil 


Cotton  stearin 
Lard.. 


Olive  oil 


Peanut  oil .... 

Palm  oil 

Sesame  oil. . . . 
Theobroma  oil 

Seal  oil 

Rape  oil 

Cocoanut  oil . . 


Butter  fat,  lowest . . 

highest.. 

"  common 

mum. 


maxi- 


95.75 

95.28 

95.73 

87.41 

95.56 

95.75 

94.29 

95.5 

96.15 

95.43 

95.09 

95.00 

95.6 

95.48 

94.59 

90.68 

95.10 

86.43 

80.78 

86.6 

88.5 

87.5 


Theoretical  quantity. 


HEHNER'S  determinations. 

(BENSEMANN). 

(E.  WALLER,  1886). 

(MUTER). 

(WEST-KNIGHTS). 

u 

(E.  WALLER). 

a 

(HEHNER). 

(E.  WALLER). 

(BENSEMANN). 

(E.  WALLER). 

(BENSEMANN). 

(MOORE). 

(E.  WALLER). 

(HEHNER  and  ANGELL). 


Butter  fat,  lowest  of  nine . . . 
"          highest      "      ... 

From    26    genuine  I  lowest. 
American  butters,  j"  highest 

From    25     butters,  )  lowest. 
Pennsylvania  .  . . .  j  highest 


88 
89 


•jjg  i  WILEY, Washington,  1884. 

86.40  )  E.  WALLER, 

90.24  j  New  York,  1886. 


86.7 
87.7 


C.  B.  COCHRAN,  1886. 


DETERMINATION  OF  FAT  ACIDS. 


257 


Saponification  Coefficients :  Kottstorfer*  s  Numbers  (p.  254). 
(Milligrams  of  KOH  neutralized  in  saponifying  1  gram  of  Fat.) 

Stearin 188.8  By  calculation. 

Olein 190.0  " 

Palmitin 208.0  " 

Butyrin 557.3  " 

Beef  Tallow 196.5  KOTTSTORFER. 

k<           "      commercial 196.8  " 

Mutton  Tallow 197.0  " 

Lard 195.7  " 

Olive  oil 191.8  " 

Eape    " 178.7  " 

(mean...     227.0  « 

Butter  Fat. ...'...  -I  lowest. .     221.5  " 

(  highest.     233.0  « 
Fat  of  Rancid  Butter — about 

1.5  lower  than  when  fresh.  " 

Cocoanut  oil 250.3  (MooEE,  1884). 

"          "  washed 246.2  " 

"          "  49.3$,  Oleomar- 

garin  50.70 220.0  " 

Cocoanut  oil  70.2$,  Oleomar- 

garin  29.8$ 234.9  « 

Almond  oil,  sweet 194.7-196.1  (YALENTA,  1883). 

Apricot  oil 192.9  " 

Bitter  Almond,  fixed  oil . .         194. 5 

n             -i                                   j     181-°  " 

Castor  Ol1 j  176-178  (ALLEN,  1884). 

Cotton-seed  oil 195  (YALENTA). 

Lard  oil 191-196  (ALLEN). 

T.         ,     .,                               189-195  " 

Lmseed011 195.2  (MOORE). 

191.7  (YALENTA). 

Olive  oil 191-196  (ALLEN). 

185.2  (MOORE). 

p             n                              j     191.3  (YALENTA). 

Peanut011 I    196.6  (MooBE). 

Sesame  oil 190.0  (YALENTA). 

Sperm  oil 130.0-134.4  (ALLEN). 

Theobroma  oil 199.8  (MOORE). 

Train  oil 190-191  (ALLEN). 

Messrs.  WALLER  and  MARTIN  (1886 :   Report  of  the  Dairy 


258  FATS  AND   OILS. 

Commissioner  of  the  State  of  New  York)  obtained,  from  25  genu- 
ine American  butters,  Kottstorfer's  numbers  from  220.6  to  230.1 
(extremes)  ;  a  rancid  butter,  223.0  ;  the  same  deodorized,  219.45  ; 
and  from  the  insoluble  fat  acids  of  a  butter,  214.25.  From  oleo- 
margarin  188.65;  another,  191.6.  From  mutton  suet,  203.25  ; 
beef  suet,  199.2;  lard,  195.85.  From  cottonseed  oil,  162.0  to 
193.05  ;  average  of  five,  183.47. 

(4)  Determination  of  Fat  Acids  by  their  capacity  of  combi- 
nation with  iodine. — The  fat  acids,  whether  free  or  in  their 
glycerides,  form  combinations  with  iodine,  bromine,  or  chlorine. 
One  molecule  of  oleic  acid  or  ricinoleic  acid  takes  two  atoms  of 
iodine ;  one  molecule  of  linoleic  acid,  four  atoms  of  iodine ;  ad- 
dition products  being  formed. 

The  directions  of  HUBL  1  for  finding  the  percentage  of  iodine 
taken  into  combination  (the  iodine  number)  are  as  follows,  com- 
mencing with  preparation  of  the  needful  reagents :  (I)  Iodine 
solution.  Of  iodine  25  grams  are  dissolved  in  500  c.c.  of  alcohol 
(free  from  fusel  oil);  of  mercuric  chloride  30  grams  are  dissolved 
in  500  c.c.  of  the  alcohol,  and  this  solution  filtered  if  necessary ; 
when  the  two  solutions  are  united,  and,  after  6  to  12  hours' 
standing,  titrated  with  the  standardized  thiosulphate  solution, 
and  the  standard  noted. — (2)  Thiosulphate  solution.  A  solution 
of  about  24  grams  of  sodium  thiosulphate  in  the  liter  is  made, 
and  its  iodine  value  accurately  determined  with  a  weighed  quan- 
tity of  freshly  sublimed  iodine.  About  0.2  gram  of  resublimed 
iodine  is  placed  in  a  small  glass  tube  closed  at  one  end  and  pro- 
vided with  a  similar  tube  enough  larger  to  serve  as  a  cover,  both 
tubes  being  previously  dried  and  weighed.  The  iodine  is  heated 
in  the  inner  tube,  on  a  sand-bath,  until  it  melts,  then  covered  with 
the  outer  tube,  cooled  in  a  desiccator,  and  weighed.  The  cover  is 
now  removed  and  both  tubes  are  placed  in  a  stoppered  flask  con- 
taining 1  gram  of  potassium  iodide  (neutral  and  free  from  iodine) 
dissolved  in  10  c.c.  of  water.  When  the  iodine  has  dissolved,  the 
solution  of  thiosulphate  of  sodium  is  added  from  a  burette  until 
the  iodine  color  is  reduced  to  a  faint  yellow,  a  little  starch  solu- 
tion is  added,  and  the  titration  completed  to  the  extinction  of 
the  blue  color.  The  iodine  value  of  the  thiosulphate  solution  is 
now  written. — (3)  Chloroform.  The  purity  of  chloroform  is  as- 
sured for  this  assay  by  digesting  10  c.c.  of  it  with  10  c.c.  of  the 
iodine  solution  at  ordinary  temperature  for  two  or  three  hours' 
and  titrating  to  the  extinction  of  the  iodine  with  the  thiosul- 

1 1884:  Ding.  pol.  Jour.,  253,  281;  Jour.  Chem.  Soc.,  46,  1435;  Am.  Ghem. 
Jour.,  6,  285. 


DETERMINA  TION  OF  FAT  ACIDS.  259 

phate  solution,  the  stated  quantity  of  which  should  be  consumed. 
— (4)  Potassium  iodide  solution.  One  part  of  pure  iodide  of  potas- 
sium in  10  parts  of  water.  It  should  be  neutral  in  reaction,  and 
should  not  contain  any  free  iodine. 

For  the  assay,  0.2  to  0.3  gram  of  a  drying  oil,  or  0.3  to  0.4 
gram  of  a  non-drying  oil,  or  0.8  to  1.0  gram  of  a  solid  fat,  is 
taken  in  a  close-stoppered  fiask  of  about  200  c.c.,  and  10  c.c.  of 
the  chloroform  are  added  for  solution.  Of  the  iodine  solution 
20  c.c.  are  added  in  exact  measure,  and,  if  the  mixture  does  not 
become  clear  after  shaking,  a  little  more  chloroform  is  added. 
The  Quantity  of  iodine  should  be  sufficient  to  leave  a  dark  brown 
color  after  one  and  a  half  or  two  hours'  standing,  the  time  to  be 
taken  for  the  reaction.  In  titrating  the  remaining  excess  of  the 
iodine,  10  to  15  c.c.  of  the  potassium  iodide  solution  and,  after 
shaking,  150  c.c.  of  water  are  added,  when  the  thiosulphate  solu- 
tion is  added,  with  shaking,  until  the  color  of  both  the  aqueous 
layer  and  the  chloroform  layer  is  reduced  to  a  pale  yellow,  when 
starch  solution  is  introduced  and  the  extinction  of  the  iodin  \ 
completed.  For  close  results  the  iodine  and  thiosulphate  solu- 
tions should  be  standardized  just  before  or  after  the  assay.  The 
number  of  parts  of  iodine  taken  by  100  parts  of  the  fat  is  known 
as  its  iodine  number.  Using  a  sufficient  excess  of  iodine  in  the 
reaction,  quite  constant  results  are  promised. 

Iodine  Numbers. 

rn  •       -A  n    TT    r\  f        90  07         By  calculation. 

(Jleic  acid,  (Jiolio^Uo «  OA  0  ,     n~  -     -nj 

(  89.8  to  90.5     By  experiment. 

Bicinoleic  acid,  C18H34O3.  . .  85.24          By  calculation. 

Linoleic  acid,  C16H28O2 201.59  "  " 

Linseed  oil 158     (HUBL).  155.2  (MooRE).1 

Hempseed  oil 143         " 

Walnut  oil 143         " 

"  " 


Cotton-  seed  oil  

106 

it 

108.7       " 

Sesame  oil  

106 

u 

102.7       " 

Rape  and  Rubsen  oils  .... 
Olive  oil  

100 

82.8 

u 
c< 

103.6       " 
83.0        " 

Olive-seed  oil  .    

81.8 

u 

Castor  oil  

84.4 

u 

Almond  oil  (sweet)  

98.4 

u 

98.1        " 

Mustard  oil  (fixed)  

96.0 

R.  W.  MOORE,  1885:  Am.  Chem.  Jour.,  6,  416. 


26o  FATS  AND   OILS. 

Bone  oil 68.0     (HUBL). 

Cod-liver  oil 123  to  141  (KREMEL). 

Lard . . 59.0    (HUBL).  61.9  (MOORE). 

Oleomargarin 55.3         «  50.0        « 

Palm  oil 55.5         "  50.3        « 

Tallow...    40.0  " 

Wool  fat. . , 36.0  « 

Cacao    butter    (theobroma 

oil) 34.0  « 

Mace  oil  (nutmeg  butter). .  31.0  " 

Butter  fat 31.0  "     32.8  to  38.0        " 

"        "    very  old 19.5        " 

Cocoanut  oil 8.9  "                   8.9        " 

Japan  wax 4.2  " 

Fat  acids  of  bone  oil 57.4        (MOBAWSKI  and  DEMSKI). 

Fat  acids  of  tallow  of  beef.  25.9  to  32.8  "  " 

Fat  acids  of  cocoanut  oil. .     8.4  to  8.8  "  " 

Fat  acids  of  linseed  oil ....  155.2  to  155.9  "  « 

Fat  acids  of  olive  oil 86.1  «  " 

Fat  acids  of  cotton  seed  oil.  110.9  to  111.4  «  « 

Fat  acids  of  castor  oil 86.6  to  88.3  "  " 

Mineral     oils     (petroleum, 

shale) Seldom  above  14    YALENTA  (1884). 

Eosin  oils. 43  to  48  " 

Messrs.  WALLER  and  MARTIN  (1886 :  Eeport  of  N.  Y.  State 
Dairy  Commissioner)  found  Htibl's  numbers  as  follows : 

Ayrshire  butter 34.7 

Jersey          "     sweet  cream 36.7 

"   '            "     sour  cream 30.5 

Native         " 30.5 

Devon          "     sour  cream 37.0 

Eancid         « 40.5 

Oleomargarin 50.9  to  54.9 

Cotton-seed  oil 108.4 

Linseed  oil  (average  of  2). . . 165.4 

Cocoanut  oil  (average  of  2) 7.8 

Commercial  Stearin..  1.7 


DETERMINATION  OF  FAT  ACIDS.  261 

(5)  Estimation  of  Stearic  and  Palmitic  Acids  separately  in 
mixtures  of  the  two,  by  the  mean  molecular  weight  of  the  mix- 
ture.— The  molecular  weights  of  stearic  and  oleic  acids,  284  and 
282,  do  not  differ  from  each  other  enough  to  give  any  value  to 
this  method  applied  to  mixtures  of  these  two  acids.     It  is  appli- 
cable to  tallows  from  which  the  olein  has  been  removed  by  pres- 
sure.— About  50   grams  are  treated   for  the  separation   of  the 
fat  acids,  by  digesting  with  40  c.c.  potassium  hydrate  solution 
of   sp.  -gr.  1.4,  and  40  c.c.   of  alcohol.      After  boiling  to  full 
saponification,  one  liter  of  water  is  added  and  the  liquid  boil- 
ed about  three-fourths  of  an  hour  to  remove  the  alcohol,  diluted 
sulphuric  acid  is  added  to  complete  precipitation,  the  precipitate 
is  well  washed  with  water,  melted  until  clear  of  water,  drained 
and  dried.     An  accurately  weighed  portion  of  about  5  grams  of 
the  clean  fat  acids  is  dissolved  in  alcohol,  and  titrated,  by  add- 
ing normal  or  other  standard  solution  of  alkali  in  some  excess, 
using  phenol- phthalein  as  an  indicator,  and  bringing  back  the  neu- 
tral point  by  a  corresponding  solution  of  acid,  when  the  number 
(n)  of  c.c.  of  normal  solution  of  alkali  for  saturation  of  1  gram 
of  the  fat  acids  is  found.     Then  1000  -r-  n  =  mean  molecular 
weight.     Now  let  x  be  the  desired  per  cent,  of  the  one  fat  acid, 
and  b  its  molecular  weight;  y  the  desired  per  cent,  of  the  other 
acid,  and  c  its  molecular  weight — while  a  is  the  mean  molecu- 

Ct         -r  /* 

lar  weight  as  found  from  titration.     Then  x  =  100  = ,  and 

0  —  c 

y  =  100  —  x.    With  stearic  and  palmitic  acids  x  =  100 — . 

28 

(6)  Determination   of  Specific  Gravity  of  the  Fats. — The 
determination  of  the  liquid  fats  is  made  at  customary  standard 
temperatures,  as  of  other  liquids,  by  weight  in  a  specific-gravity 
bottle,  or  a  Sprengel's  tube,  or  by  a  hydrometer.     The  specific 
gravity  of  the  waxes  and  very  hard  fats  is  usually  taken  in  the 
solid  state,  at  customary  temperatures,  and  so  stated.     In  case  of 
many  fats,  however,  the  density  of  the  solid  state  is  measurably 
dependent  upon  the  conditions  of  solidification.  •  And  the  speci- 
fic gravity  of  the  softer  solid  fats  is  more  often  taken  in  the 
liquid  state,  at  some  stated  temperature  well  above  the  melting 
point— by  Stoddart  at  100°  C.,  by  Muter  at  37.8°  C.  (100°  F.)— 
and  usually  taking  water  at  the  same  temperature  as  the  stand- 
ard. 

In  adjusting  the  temperature  of  a  specific-gravity  bottle  or  a 
Sprengel's  tube,  immersion  in  water  is  employed.  The  water  is 
warmed  in  a  beaker,  or  other  convenient  vessel,  in  which  the 


262  FATS  AND   OILS. 

gravity  bottle  or  tube  is  securely  suspended,  the  filling  up  of  the 
exact  volume  of  the  liquid  fat  being  adjusted  at  the  noted  tem- 
perature. Then  the  operation  is  repeated  with  water  instead 
of  fat,  to  obtain  the  divisor  representing  the  unit  of  density. — 
The  Westphal  balance  is  conveniently  employed,  the  counter- 
poise being  suspended  and  weighed  in  the  oil,  contained  in  a 
vessel  surrounded  by  water  in  a  larger  vessel  to  which  heat  is 
applied. 

To  take  the  specific  gravity  of  a  melted  fat  by  the  hydro- 
meter, a  small  hydrometer  is  most  convenient,  and  the  oil  is 
contained  in  a  corresponding  small  cylinder  which  can  easily  be 
immersed  in  a  hot  water-bath.  A  constant  water-bath  of  constant 
temperature  is  convenient  for  habitual  use  in  this  operation. 

Methods  by  dropping  into  liquids  of  known  and  adjusted 
density  have  been  proposed  by  chemists.  HAGER  (1880)  drops 
melted  fat  into  alcohol,  keeping  the  drops  separate,  then  transfers 
them  to  mixtures  of  alcohol,  water,  and  glycerine,  until  an  equi- 
librium is  found.  A  list  of  densities  of  fats  and  resins,  so  deter- 
mined, is  published.1  A  similar  method  was  proposed  for  butter 
fat,  using  methylated  spirit,  by  CASSAMAJOR  (1881),  and  further 
described  under  Butter.  The  counterpart  principle,  of  employ- 
ing specific-gravity  beads  of  graded  density,  has  been  developed 
by  Mr.  WIGNER  (18763),  especially  for  melted  fats. 

BLYTH  recommends  taking  the  specific  gravity  of  butter  fat, 
clarified  and  filtered,  as  a  solid  at  15°  C.,  by  weight  in  suspension 
in  water,  with  a  weighted  tube,  on  the  general  plan  of  solids 
lighter  than  water.3 

The  ratio  of  expansion  of  butter  fat,  lard,  etc.,  on  increase  of 
temperature,  has  been  reported  on  by  WIGNER  (18794). 

SPECIFIC  GRAVITIES  or  FAT  OILS  classified  by  BENEDIKT,  tak- 
ing figures  of  ALLEN  (1884),  and  others,  at  15°  C.  : 

A.  Sp.  gr.  under  0.883 . .    1.  Liquid  waxes  from  ma- 
rine animals : 

Sperm  oil 0.875-0.883 

,  2.  Oils  of  unknown  com- 

position : 

Shark  oil 0.865-0.867 

African  fish-oil 0.867 

lZeitsch.  anal.  Chem.,  19,  239;  Jour.  Chem.  Soc.,  38,  70;  Phar.  Jour. 
Trans.,  [3],  10,  287. 

2  Analyst,  I,  145.  3 1880:  Analyst,  5,  76.  4  Analyst,  4,  183. 


DETERMINATION  OF  FAT  ACIDS.  263 

B.  0.883  to  0.912 Oil  from  cranial  cavities  : 

Liquid    waxes    with 

glycerides 0.908 

C.  0.912  to  0.920 1.  Non-drying  oils : 

Almond  oil 0.917-0.920 

Peanut  oil. 0.916-0.920 

Olive  oil 0.914-0.917 

Mustard  oil 0.914-0.920 

2.  Oils  of  marine  animals.        none. 

3.  Oils  of  land  animals  : 

Lard  oil 0.915 

Tallow  oil 0.916 

Neat-foot  oil 0.914-0.916 

Bone  oil 0.914-0.916 

D.  0.920  to  0.937 1.  Vegetable  oils  : 

(a)  Feebly  drying,  sp. 
gr.     less      than 
0.930: 
Cotton-seed  oil. . .   0.922-0.930 

i  Sesame  oil 0.923-0.924 

Sunflower  oil 0.924-0.926 

(J)   Strongly   drying 
oils  : 

Hempseed  oil 0.925-0.931 

Linseed  oil 0.930-0.935 

Poppy  oil 0.924-0.937 

Walnut  oil 0.925-0.926 

2.  Oils  of  marine  animals  : 

Cod-liver  oil 0.923-0.930 

3.  Oils  of  land  animals . .         none. 

E.  Sp.  gr.  above  0.937. .    1.  Vegetable  oils.    Of  ca- 

thartic effect: 

Croton  oil 0.942-0.943 

Castor  oil 0.960 

(Boiled  linseed  oil.) 
2.  Oils  of  land  animals . .        none. 

SPECIFIC  GRAVITIES  OF  FAT  OILS  at  15°  C.  (MUNICIPAL  LA- 
BORATORY OF  PARIS,  1884) : 

Almond  oil 0.917       Olive  oil 0.9163 

Peanut  oil.  ,   0.917          "       "common..      .   0.9163 


264 


FATS  AND   OILS. 


Colza  oil 0.9154 

Cotton-seed  oil  (white) .  0.9254 

"        "      «  (brown).  0.930 

Beechnut  oil 0.922 

Linseed  oil. 0.9325 

Cameline  oil 0.9252 

Walnut  oil 0.926 

Poppy  oil 0  925 

Tallow  oil. . 


Sesame  oil 0.9226 

Norwegian  whale  oil. . .   0.9257 
South  Sea      "      "   . 
American       "      "   . 
Cod- liver  oil  (pale) . . 
"       "       "    (brown) 

ISTeat-foot  oil 0.9142 

Sheep-foot  oil 0.9187 

.   0.9029. 


0.927 
0.925 
0.928 
0.9254 


To  compare  the  specific  gravity  of  one  oil  with  that  of  an- 
other  oil  (DONNY,  1864):  Color  the  one  oil  with  alkanet  or 
other  tinctorial  matter,  and,  while  both  oils  are  at  same  tempera- 
ture, let  fall  a  few  drops  of  the  colored  oil  into  a  portion  of 
the  other  in  a  test-tube. 

SPECIFIC  GRAVITIES  OF  SOLID  FATS  at  15°  C.  (DIETERICH, 
1882) : 

Wax,  white 0.973          Common     Resin, 

"      yellow 0.963-0.964        American 1.108 

"      Japan 0. 975          Common     Resin, 

Ceresin,  white . . .         0.918  French 1.104-1.105 

"     half  white.         0.920          Theobroma  oil .  . .    0.980-0.981 
"      yellow  . . .         0.922          Paraffin,  medium.    0.913-0.914 

Ozokerite,  crude  .         0.952          Tallow,  beef 0.952-0.953 

Spermaceti. . 0.960  "       sheep 0.961 

"Stearin" 0.971-0.972. 

SPECIFIC  GRAVITIES  OF  SOLID  FATS  at  15°  C.    HAGER  (1879) : 

Butter  Fat,  clarified 0.938-0.940 

"           several  months  old 0.936-0.937 

Artificial  butter 0.925-0.930 

Lard,  fresh 0.931-0.932 

Tallow,  beef 0.925-0.929 

"       sheep 0.937-0.940 

Cocoanut  oil,  fresh 0.950-0.952 

"             very  old 0.945-0.946 

Stearic  acid,  melted 0.946 

"         "      crystallized 0.967-0.969 

Beeswax,  yellow 0.959-0.962 

Ceresin,  yellow 0.925-0.928 

"         white .  0.923-0.924 

"         very  pure  white 0.905-0.908 

Common  resin. .  1.100 


DE TERMINA  TION  OF  FAT  A CIDS.  265 

SPECIFIC  GRAVITIES  OF  SOLID  FATS.  At  100°  (7.,  compared 
with  water  at  15°  C.  BENEDIKT  (1886),  from  ALLEN  (1884)  and 
KONIGS  (1883) : 

A.  Fats  not  containing  glycerides  of  lower  fat  acids  : 

1.  Vegetable  :  Theobroma  oil 0.857 

Palm  oil 0.857 

Japan  wax. 0.873 

2.  Animal :      Lard. 0.861 

Tallow  (beef  or  mutton) 0.860 

Horse  fat. 0  861 

Oleomargarin 0.859 

B.  Fats  containing  glycerides  of  lower  (volatile)  fat  acids : 

1.  Vegetable :  Cocoanut  oil 0.863 

,      Palm-kernel  oil .• 0.866 

2.  Animal:      Butter  fat. .  0.865-0. 


(7)  Determination  of  the  Melting  and  Congealing  Points  of 
Fats. — A  simple  method  of  finding  the  melting  point  is  that  of 
the  inspection  of  the  fat,  taken  congealed  on  the  bulb  of  a  ther- 
mometer, in  a  beaker  of  water  to  which  heat  is  applied,  as  de- 
scribed under  Stearic  acid,  a. 

Sometimes  a  few  drops  of  the  melted  fat  are  taken  up  in  a 
glass  tube  of  1  to  3  millimeters  internal  diameter,  bound  against 
the  bulb  of  a  thermometer,  congealed,  and  immersed  in  a  beaker 
of  water  or  other  liquid  to  which  heat  is  gradually  applied.  The 
capillarity  of  the  tube  influences  the  movement  of  the  fat,  so 
that  the  melting  point  obtained  in  this  way  is  somewhat  higher 
than  that  obtained  by  observation  of  the  fat  taken  as  a  coating 
of  the  thermometer  bulb.  Some  observers  have  wider  tubes — 
taking  a  "  funnel-tube  "  of  about  2  centimeters  diameter  in  the 
upper  portion  and  7  millimeters  diameter  in  the  lower  portion— 
a  few  drops  of  the  melted  fat  being  taken  and  congealed  on  the 
side  of  the  wider  part,  just  above  the  narrowing  of  the  tube. 
Some  authors  designate  the  "  beginning  of  the  melting  point " 
as  the  temperature  at  which  the  fat  begins  to  flow  down  the  side 
of  the  tube,  and  "  end  of  the  melting  point "  as  that  at  which  it 
becomes  wholly  liquid. 

The  sinking  point  of  HEHNEK  and  ANGELL  is  the  temperature 
at  which  a  glass  bulb  of  3.4  sp.  gr.  and  1  c.c.  in  volume  will  sink 
in  the  melted  fat.  The  bulb  is  blown  from  a  piece  of  glass  tub- 
ing of  £  inch  diameter,  and  is  drawn  off  pear-shaped  with  a  very 


266  FA  TS  AND  OILS. 

tapering  end.  The  bulb  should  displace  as  nearly  as  possible 
1  c.c.  of  water,  and  should  be  so  weighted  by  the  introduction  of 
mercury  as  to  weigh  3.4  grams.  Differences  of  0.005  to  0.01 
weight  have  little  effect  on  the  results.  The  following  directions 
for  taking  "the  sinking  point"  of  butter  will  indicate  the 
method  of  application  to  any  fat.  Of  the  butter  20  to  30  grams 
are  melted  in  a  beaker  over  the  water-bath,  then  poured  into  a 
test-tube  }  inch  wide  and  6  inches  long,  filling  to  within  two 
inches  of  the  top.  The  tube  is  kept  warm  until  the  fat  is  clarified 
by  the  settling  of  the  water,  curd,  and  salt, when  the  fat  is  solidified 
at  15°  C.  by  immersing  the  tube  in  water  of  this  temperature. 
(The  cone  of  depression  on  the  top  of  the  fat  serves  to  indicate 
its  relative  fusing  point.  Pure  butter  fat  shows  only  a  slight 
depression,  while  admixtures  with  fats  of  high  melting  points 
show  a  considerable  hollow  cone.)  The  tube  is  now  placed  in 
about  one  liter  of  cold  water,  in  a  beaker,  the  test-tube  being  se- 
cured so  that  the  top  of  the  fat  is  about  1^-  inches  below  the  sur- 
face of  the  water.  Heat  is  now  applied  to  the  beaker  by  a  sand- 
bath  or  by  asbestos  felt,  over  a  lamp.  The  surface  of  the  fat  is 
made'level,  and  the  weighted  bulb  placed  thereon.  The  water  is 
stirred  from  time  to  time.  A  thermometer  is  placed  in  the  water, 
with  the  bulb  near  the  surface  of  the  fat,  and  the  temperature 
read  off  just  as  the  globular  part  of  the  bulb  has  sunk  beneath 
the  fat. 

Hehner  and  Angell  found  the  average  sinking  point  of  the 
fat  of  24  genuine  butters  to  be  35.5°  C.  (96°  F.),  with  extremes 
of  34.3°  to  36.3°  C.  (93.7°-97.3°  F.)  Of  the  fatty  acids  of  but- 
ter fat,  40.5°  to  42.1°  C.  Of  beef  tallow,  average,  50.6°  C.  (48.3° 
to  53.0°  C.);  of  mutton  tallow,  50.9°  C.  average  (50.1°  to  51.6° 
C.) ;  of  lard,  41.1°  to  45.3°  C. ;  of  stearin,  62.86C. ;  of  cacao  but- 
ter, 34.9°  C.  ;  of  palm  oil,  39.2°  C.  To  calculate  the  mean  sinking 
point  of  a  mixture  of  two  fats  of  known  composition,  having 
their  respective  sinking  points  (Sx  and  S2),  and  percentages  in  the 
mixture  (Fx  and  F3)  : 

^lX   T^t(J2><S2)  =  sinking  point  of  the  mixture.     Kesults 

•^  1    I    ^  2 

of  admixture  are  compared  with  calculated  averages,  as  follows : 

66.7$  butter  and  33.3$  tallow,  43.1°  C.  found,  42.08°  C.  calculated. 
73.0  "  27.0  "  42.3  "  '  40.2  " 

10.0          «  90.0         "      48.8  "        49.6  « 

85.0          "  15.0         "      38.1  «        38.1  " 

HASSALL  uses  a  light  bulb,  weighing  0.18  gram,  and  of  the 
volume  of  about  0.5  c.c.,  sunken  in  the  solidified  fat  in  a  test- 


DETERMINA  TION  OF  FA  T  ACIDS. 


267 


tube  \  inch  wide  and  4  inches  high.  "  The  rising  point "  is 
taken  at  the  temperature  when  the  bulb  rises,  during  the  gradual 
application  of  heat,  by  the  softening  of  the  fat.  Hassall  also  re- 
cords "thejtt*n4  of  clearance"  when  the  fat  becomes  clear,  this 
point  being  usually  1°  or  2°  C.  above  the  rising  point. 

The  congealing  point  is  more  often  inconstant  than  the  melt- 
ing point.  It  is  sometimes  taken  as  the  point  of  commencing 
turbidity  in  a  mass  of  melted  fat,  and  sometimes  as  the  point  of 
formation  of  a  coherent  solid.  DALICAN  made  determination  of 
the  congealing  point  by  use  of  a  test-glass  10  or  12  centimeters 
(4  or  5  inches)  long  and  1.5  or  2  centimeters  (0.4  or  0.5  inch) 
wide.  The  tube  is  two-thirds  filled  with  the  fat,  warmed,  and 
the  fat  stirred  with  a  glass  rod,  to  liquefy  the  contents.  A  ther- 
mometer, graduated  in  fifths,  is  suspended  in  the  fat,  loosely  ad- 
justed by  a  perforated  cork  at  the  mouth  of  the  tube,  the  bulb 
resting  in  the  centre  of  the  fat.  When  crystallization  commences 
on  the  edge  the  mass  is  stirred  with  the  bulb  of  the  thermometer, 
by  which  the  temperature  is  caused  to  fall  a  little,  after  which  it 
soon  rises  to  near  the  point  before  noted,  and  when  it  stands 
constant  for  two  minutes  the  temperature  is  taken  as  the  con- 
gealing point.  Some  fats,  in  congealing,  show  a  rise  of  tem- 
perature after  the  solidification  has  fairly  set  in,  and  the  maximum 
of  this  rise  is  sometimes  taken  as  the  congealing  point  (see  the 
table  at  p.  271). 

MELTING  AND  CONGEALING  POINTS  of  mixtures  of  Stearic  and 
Palmitic  acids  (HEINTZ)  : 


Stearic  acid. 

Palmitic  acid. 

Melting  point. 

Congealing  point. 

100^ 

Of, 

69.2°  C. 

—  .-°  C. 

90 

10 

67.2 

62.5 

80 

20 

65.3 

60.3 

70 

30 

62.9 

59.3 

60 

40 

60.3 

56.5 

50 

50 

56.6 

55 

40 

60 

56.3 

54.5 

32.5 

67.5 

55.2 

54 

30 

70 

55.1 

54 

20 

80 

57.5 

53.8 

10 

90 

60.1 

54.5 

0 

100 

62.0 

268 


FA  TS  AND  OILS. 


CONGEALING  POINT  of  mixtures  of  Solid  fat  acids  (' '  Stearic 
acid  ")  and  Liquid  fat  acid  ("  Oleic  acid")  as  obtained  from 
Tallow  (DALICAN,  1880) : 


Congealing  point. 

°C. 

"  Stearic  acid  " 
in  100  parts  of  Tallow. 

"  Oleic  acid  " 
in  100  parts  of  Tallow. 

35° 

25.20  parts. 

69.80  parts. 

35.5 

26.40 

68.60 

36 

27.30 

67.70 

36.5 

28.75 

66.25 

37 

29.80 

65.20 

37.5 

30.60 

64.40 

38 

31.25 

63.75 

38.5 

32.15 

62.85 

39 

33.45 

61.55 

39.5 

34.20 

60.80 

40 

35.15 

59.85 

40.5 

36.10 

58.90 

41 

38.00 

57.00 

•    41.5 

38.95 

56.05 

42 

39.90 

55.10 

42.5 

42.75 

52.27 

43 

43.70 

51.30 

43.5 

44.65 

50.36 

44 

47.50 

47.50 

44.5 

49.40 

45.60 

45 

51.30 

43.70 

45.5 

52.25 

42.75 

46 

53.20 

41.80 

46.5 

55.10 

39.90 

47 

57.95 

37.05 

47.5 

58.90 

36.10 

48 

61.75 

33.25 

48.5 

66.50 

28.50 

49 

71.25 

23.75 

49.5 

72.20 

22.80 

50 

75.05 

19.95 

50.5 

77.10 

17.90 

51 

79.50 

15.50 

51.5 

81.90 

13.10 

52 

84.00 

11.00 

52.5 

88.30 

6.70 

53 

92.10 

2.90 

DETERMINA TION  OF  FAT  A CIDS. 


269 


MELTING  AND  CONGEALING  POINTS  of  the  Acids  of  Solid  Fats 

(HUBL). 


Fat  acids  of 

Melting. 

Congealing. 

Oleomargarin  

42.0°  C. 

39.8°  C. 

Palm  oil  

47.8 

42.7 

Tallow 

45.0 

43.0 

Wool  fat  

41.8 

40.0 

Cacao  butter  

52.0 

51.0 

Mace  oil  (nutmeg  oil)  

42.5 

40.0 

Butter  fat       

38.0 

35.8 

Cocoanut  oil  .  .  .  .  

24.6 

20.4 

MELTING  AND  CONGEALING  POINTS  of  the  Fat  Acids  of  Oils  (BACH). 


Fat  acids  of 

Melting. 

Congealing. 

Olive  oil  

26.5-28.5°  C. 

Not  under  22°  C. 

Cotton-seed  oil  

38.0 

35.0 

Sesame  oil  

35.0 

32.5 

Peanut  oil  

33.0 

31.0 

Sunflower-seed  oil  

23.0 

17.0 

Rape  oil  

20.7 

15.0 

Castor  oil  

13.0 

2.0 

270 


FA  TS  AND  OILS. 


CONGEALING  POINT  of  mixtures  of  certain  proportions  of  com- 
mercial Stearic  acid  of  stated  melting  points,  as  obtained 
from  TaUow  (SCHEPPER  and  GEITEL,  1882). 


Congealing  point 
of  the  tallow-  fat 
acids. 

The  tallow-  fat  acids  containing  in  per  cent,  of  '  'Stearic  acid  " 
of  congealing  point  of 

48°  C. 

50°  C. 

52°  C. 

54.8°  C. 

10°  C. 

3.2 

2.7 

2.3 

2.1 

15° 

7.5 

6.6 

5.7 

4.8 

20° 

13.0 

11.4 

9.7 

8.2 

25° 

19.2 

17.0 

14.8 

12.6 

30° 

27.9 

23.2 

21.4 

18.3 

35° 

39.5 

34.5 

30.2 

25.8 

36° 

42.5 

36.9 

32.5 

27.6 

37° 

46.0 

40.0 

34.9 

29.6 

38° 

49.5 

42.6 

37.5 

32.0 

39° 

53.2 

458 

40.3 

34.3 

40° 

57.8 

49.6 

43.5 

37.0 

41° 

62.2 

53.5 

47.0 

40.0 

42° 

66.6 

57.6 

50.5 

42.9 

43° 

71.8 

62.0 

54.0 

46.0 

44° 

77.0 

66.2 

58.4 

49.8 

45° 

81.8 

71.0 

62.6 

53.0 

46° 

87.5 

75.8 

67.0 

56.8 

47° 

93.3 

80.9 

71.5 

60.8 

48° 

100.0 

87.2 

76.6 

65.0 

49° 

93.0 

81.7 

69.5 

50° 

100.0 

87.0 

74.5 

51° 

93.5 

79.8 

52° 

100.0 

84.8 

53° 

90.1 

54° 

95.3 

54.8° 







100.0 

CONGEALING  POINTS  of  Oils  (MUNICIPAL  LABORATORY  OF  PARIS). 


Olive  oil  

4-  2°C 

Cod-liver  oil... 

0 

Rape  oil  

—  3.75 

Colza  oil 

.    —  6.25 

Peanut  oil  
Almond  oil.  . 

-  7 
.    -10 

-17.5°  C. 

—18 


Beechnut  oil 
Cameline  oil 
Poppy  oil  ........    —18 

Linseed  oil  .......    —27.5 

Hempseed  oil  .....    —27.5 


DE  TERM  IN  A  TION  OF  FA  T  ACIDS. 


271 


MELTING  AND  CONGEALING  POINTS  of  Solid  Fats,  WIMMEL  (1868). 


Melting  point. 

In  congealing  be- 
come turbid  at 

In  congealing, 
temp,  rises  to 

Tallow,  1)eef  ,  fresh.  .  .  . 
«          "     old  

43°  C. 
42.5 
47 
50.5 
41.5-42 
31-31.5 
32.5 
52.5-54.5 
33.5-34 
24.5 
30 
36 
42 
43.5-44 

62-62.5     )  c 
44-44.5     j 

33°  C. 
34 
36 
39.5 
30 
19  20 

36-37°  C. 

38 

40^:1 

44-45 
32 
19.5-20.5 
25.5 
45.5-46 
27-29.5 
22-23 
21.5 
35 
39.5 
41.5-42 
3low  the  melt- 
dthout  devel- 
rarmth. 

"       sheep,  fresh..  . 
"           "       old.  .  .  . 
J,ard.              

Butter  fat   fresh 

Firkin  butter  

24 
40.5-41 

20.5 
20-20.5 
21 
24 
38 

;    33 

congeal  just  bi 
ing  point  ^ 
opment  of  ^ 

Japan  wax       

Cacao  butter  

Cocoanut  oil  

Palm  oil,  fresh,  soft.. 
"            "      hard. 
"         old  

Mace  oil  (nutmeg  oil). 
Beeswax,  yellow  

Spermaceti  

Other  Authorities 


Isocholesterin  

137-138 

Ceresin  (ozokerite).  .  .  . 
Cetyl  alcohol  

58-84 
50 

Ceryl  alcohol  

79 

Myricyl  alcohol 

85 

2/2 


FATS  AND  OILS. 


STEARIN  PERCENTAGE  IN  OLEOMARGARIN,  ACCORDING  TO  CONGEAL- 
ING POINTS/ 


Congealing 
at°C. 

Per  cent,  of 
Stearic  ac. 
of±S°C.* 

Congealing 
at  °C. 

Per  cent,  of 
Stearic  ac. 
of  48°  C. 

Congealing 
at°C. 

Per  cent,  of 
Stearic  ac. 
o/48°  C. 

5.4° 

20° 

12.1 

35° 

39.5 

6 

6.3 

21 

13.2 

36 

43.0 

7 

0.8 

22 

14.5 

37 

46.9 

8 

1.2 

23 

15.7 

38 

50.5 

9 

1.7 

24 

17.0 

39 

54.5 

10 

2.5 

25 

18.5 

40 

58.9 

11 

3.2 

26 

20.0 

41 

636 

12 

3.8 

27 

21.7 

42 

68.5 

13 

4.7 

28 

23.3 

43 

73.5 

14 

5.6 

29 

25.2 

44 

78.9 

15 

6.6 

30 

27.2 

45 

83.5 

16 

7.7 

31 

29.2 

46 

89.0 

17 

8.8 

32 

31.5 

47 

94.1 

18 

9.8 

33 

33.8 

1  48 

100.0 

19 

11.1 

34 

36.6 

EUDORFF  (1872). 


Melting  point. 

Congealing  point. 

In  congealing,  tem- 
perature rises  to 

Yellow  wax.  .  .  . 
White  wax  .... 
Paraffin.   . 

63.4 

61.8 
49  6 

61.5,  62.6,  62.3 
61.6 
49  6 

« 

52  5   54  0 

53  0 

a 

53  0 

52  9 

a 

52  7,  53  2 

52  7 

Spermaceti  

« 

Stearic  acid, 
commercial 

Japan  wax  

43.5 
44.1,  44.3 

(         55.3 
\    56.2,  56.6 
(    56.0,  56.4 
50  4  51  0 

43.4 
44.2 
55.2 

55.8 
55.7 

50.8 

Cacao  butter.  .  . 
Mace    oil    (nut- 
meg)   

33.5 

70,  80 



27.3 
41.7,  41.8 

Tallow,  sheep.  . 

a                a 

46.5,  47.4 
43.5,  45.0 

32,  36 

27,  35 

j     a  few  de- 
|       grees. 

1  BENEDIKT'S  "Analyse  der  Fette,"p.  131. 


8  Congealing  point. 


DE  TERMINA  TION  OF  FA  T  A  CIDS.  273 

(8)  Calculation  of  the  constituent  Fat  Acids  and  Neutral 
Fats,  and  the  value  for  production   of  Fat  Acids  and  Gly- 
cerin. 

Let  n  equal  the  number  of  c.c.  of  standard  solution  required 
to  saturate  the  free  fat  acids  of  1  gram  of  the  material,  taken  up 
in  alcoholic  solution,  using  phenol-phthalein  as  an  indicator,  and 
titrating  with  alkali  at  once.  Let  m  be  the  number  of  c.c.  of 
the  standard  alkali  of  the  value  of  1  c.c.  of  normal  alkali.  In 
normal  solution,  m  =  1 ;  in  decinomial  solution,  m  =  10,  etc. 
Let  G  beHhe  number  of  c.c.  of  £-  normal  alkali  taken  to  saturate 
both  the  free  and  combined  acids  in  1  gram  of  fat,  as  directed 
under  Determination  of  Mean  Molecular  Weight  (p.  261).  Let 
a  be  the  mean  molecular  weight  of  the  fat,  found  from  c,  as  di- 

M  n 

rected  on  p.  261.     Then  per  cent,  of  free  fat  acids  =  — . 

J_  \J    /\    //& 

Per  cent,  of  neutral  fat  =  100  —  per  cent,  of  free  fat  acids. 

(9)  Distinction  of  Fat  Oils  by  Solubility  in  Glacial  Acetic 
Acid  (YALENTA/  1884). — When  the  oil,  and  glacial  acetic  acid 
of  sp.  gr.  1.05662,  in  equal  volumes,  are  mixed  in  a  test-tube, 
and  if  solution  does  not  occur  at  ordinary  temperatures,  the  mix- 
ture warmed,  it  will  be  found  that — 

1.  At  ordinary  temperatures  (15°-20°  C.)  Castor  oil  and  Olive 
oil  are  perfectly  dissolved.  __rv- 

2.  At  temperatures  from  23°  C.  to  the  boiling  of  the  acid, 
solution  is  obtained  with  Palm  oil,  Mace  oil,  Cocoanut  oil,  Palm- 
kernel  oil,  Olive  oil,  Theobroma  oil,  Sesame  oil,  Almond  oil, 
Cotton-seed  oil,  Peanut  oil,  Beef   Tallow,  American  Bone   oil, 
Cod-liver  oil,  Press  Tallow.     See  table  below. 

3.  Imperfectly  dissolved  at  boiling  of  the  acetic  acid — Kape 
oils. 

For  distinctions  between  members  of  the  2d  class-  the  mix- 
ture is  heated  in  the  test-tube  until  solution  is  effected,  when  a 
thermometer  is  introduced,  and,  as  the  mixture  cools,  the  tempe- 
rature of  commencing  turbidity  is  noted: 

lDing.  pol.  Jour.,  252,  296;  Zeitsch.  anal  Chem.,  24,  295;  Jour.  Chem. 
8oc.,  48,  93;  46,  1078. 


274 


FATS  AND  OILS. 


Name  of  the  Fat. 

Sp.  Gr. 

of  the  fat. 

Turbid  at 

Remarks. 

Palm  oil        

23°  0. 

Fresh  fat. 

Mace  oil  

27 

Cocoanut  oil  

40 

Palm-kernel  oil.  ...... 

48 

Old  rancid  fat. 

Olive  oil,  green  . 

0.9173 

85 

Second    pressed, 

Theobroma  oil  

105 

probably  con- 
taining olive- 
kernel  oil. 

Sesame  oil  

0.9213 

107 

Almond  oil  

0.9186 

110 

From    sweet    al- 

Cotton- seed  oil 

0.9228 

110 

monds. 

Olive  oil,  yellow  

09149 

111 

Oil  first  pressed. 

Peanut  oil  

0.9193 

112 

Apricot  oil  

0.9191 

114 

Beef  Tallow  

95 

Very    fine    hard 

Bone  Fat  (American)  . 
Cod-liver  oil  



90-95 
101 

tallow. 

Press  Tallow. 

114 

Melt.     55.8°    C. 

Hard,  fine. 

Solubilities  of  Oils  in  Glacial  Acetic  Acid,  BARNES  (1876).— 
1  volume  of  glacial  acetic  acid  dissolves  of  fixed  oil  of  almonds, 
7  vols. ;  olive  oil,  8  vols. ;  cod-liver  oil,  7  vols. ;  linseed  oil,  7 
vols.;  turpentine  oil,  \  vol.;  copaiba  oil,  ^  vol.;  lemon  oil,  2 
vols. ;  juniper  oil,  1  vol. ;  all  proportions  of  castor  oil  and  cro- 
ton  oil. 

SEPARATION  OF  MINERAL  OILS  AND  OTHER  NON  SAPONIFIABLE 
BODIES  FROM  THE  FAT  OILS  OR  GLYCERiDES.1 — The  determination, 
in  qualitative  or  quantitative  result,  of  mixtures  of  the  FAT  OILS 
or  glycerides  with  mineral  oils  (petroleum  and  shale  oils),  tar 
oils  (neutral  coal  oils),  paraffins,  rosin  oils,  resins,  and  waxes. 
Excluding  the  few  instances  in  which  a  volatile  hydrocarbon  or 

1E.  GEISSLER,  H.  HAGER,  1880:  Summary  in  Zeitsvh.  anal.  Chem.,  19, 
114.  Lux,  \8$5:  Zeitsch.  anal.  Chem.,  24,  357.  A.  H.  ALLEN,  1881:  Chem. 
News,  44,  161;  43,  267.  Benedikt:  "  Analyse  der  Fette,"  1886,  pp.  102-126: 
"  Nachweis  und  quantitative  Bestimmung  solcher  fremder  Beimengungen, 
welche  in  der  Fettsubstanz  gelost  oder  mit  ihr  zusammengeschmolzeri  sind." 


SEPARATION  OF  MINERAL  OILS.  275 

mineral  oil  can  be  separated  from  fixed  oils  by  distillation, 
either  with  or  without  steam,  the  analysis  requires  first  the  sapo- 
nification of  the  saponifiable  substances.  Of  the  bodies  named 
above  with  the  mineral  oils,  only  the  resins  are  fully  saponifiable, 
besides  which  only  the  waxes  saponify  at  all.  The  waxes  give 
the  acids  to  alkalies  in  production  of  soap-like  compounds,  while 
the  base,  unlike  glycerin,  remains  undissolved  after  the  saponifi- 
cation. 

When  the  fat  is  readily  saponifiable,  and  especially  when  the 
non-saponifiable  substance  is  not  much  soluble  in  aqueous  soap 
solution,  simple  saponification,  with  dilution  of  the  mixture, 
serves  for  the  separation,  more  satisfactorily  with  large  quantities: 
50  grams  material  in  a  300  c.c.  flask,  with  50  c.c.  alcohol  and  40 
grams  caustic  soda  (which  will  dissolve  clear  in  alcohol),  digested 
with  stirring  at  about  90°  C.  until  dissolved,  then  boiled  for  40 
minutes,  150  c.c.  water  added  (while  boiling),  boiled  50  minutes 
longer,  and  poured  into  a  cylindrical  separator.  "When  the  non- 
saponifiable  oil  has  risen  to  a  clear  layer,  this  is  poured  off  into  a 
tared  dish,  the  surfaces  of  the  separator  and  the  liquid  washed 
with  a  few  portions  of  ether,  the  ether  evaporated,  and  the 
weight  taken. 

But  in  general  the  mineral  oils  and  resin  oil  dissolve  in  soap 
solution  to  an  extent  preventing  full  recovery  by  the  above-given 
method.  The  solubility  is  diminished  by  largely  diluting  the 
soap  solution,  but  this  is  quite  impracticable  because  it  decom- 
poses the  soap  itself,  giving  a  mixture  turbid  with  free  fat  acids. 
Therefore  it  is  necessary  to  employ  a  solvent  not  miscible  with 
aqueous  solutions — as  ether  or  petroleum  benzin — by  which  the 
paraffin  oil  or  like  un saponified  matter  may  be  "  extracted  "  from 
the  solution.  This  may  be  done  by  "  shaking  out  "  in  the  ordi- 
nary way.  Ether  is  almost  always  the  best  solvent,  giving  least 
difficulty  in  emulsification,  though  often  troublesome  in  this 
respect.  To  avoid  permanent  emulsification  the  agitation  may 
be  done  by  gently  elevating  alternate  ends  of  the  separator. 
The  details  are  given  by  ALLEN  and  THOMPSON  (1881)  in  effect 
as  follows : 

Of  the  material  5  grams  are  taken,  digested  with  25  c.c.  of  an 
alcoholic  soda  solution  (80  grams  caustic  soda  per  liter)  until 
saponification  is  complete  and  the  alcohol  evaporated,  treated 
with  50  c.c.  of  hot  water  to  dissolve  the  soap,  and  the  liquid  in- 
troduced into  a  separator  of  about  200  c.c.  capacity.  20  or  30 
c.c.  of  water  are  added,  and  when  cold  the  liquid  is  shaken  with 
30  to  50  c.c.  of  ether.  Separation  can  be  promoted  by  addition 
of  a  little  alcohol.  From  three  to  four  successive  portions  of 


276  FATS  AND  OILS. 

ether  are  usually  required.  The  residue  obtained  in  a  tared 
beaker  or  flask  by  evaporation  of  the  ethereal  solution  is  weighed. 

With  use  of  petroleum  benzin  upon  a  dried  saponilied  mass 
of  the  material  under  examination,  the  authors  last  quoted  pro- 
ceed as  follows :  10  grams  of  the  material,  in  an  evaporating- 
dish  of  five  inches  diameter,  are  digested  with  50  c.c.  of  an  eight- 
per-cent.  alcoholic  solution  of  caustic  soda,  stirring  and  gently 
boiling,  adding  15  c.c.  of  methyl  alcohol,  and  boiling  again. 
About  5  grams  of  sodium  carbonate  are  now  stirred  in,  and  then 
50  to  70  grams  of  ignited  clean  sand,  the  mixture  dried  for  20 
minutes  on  the  water-bath,  transferred  to  an  extraction  apparatus, 
exhausted  with  petroleum  benzin  (wholly  volatile  at  80°  C.),  and 
the  residue,  after  evaporation  of  this  solvent,  weighed  as  non- 
saponifiable  matters.  Ignited,  these  should  leave  only  a  trace 
of  ash.  In  presence  of  much  mineral  oil  or  resin  oil  a  portion 
of  soap  is  taken  up  by  the  benzin,  and  the  extraction  of  the  solu- 
tion by  ether  is  more  trustworthy. 

Extraction  of  the  dried  soap  with  benzin  is  carried  out  by 
DONATH  (1873),  in  analysis  of  stearin  candles  for  paraffin,  as  fol- 
lows :  6  grams  are  saponified  by  digestion  with  alcoholic  potash, 
the  alcohol  evaporated,  the  residue  dissolved  in  water,  and  the 
solution  precipitated  with  calcium  or  barium  chloride.  If  much 
paraffin  be  probably  present,  some  sodium  carbonate  is  added,  to 
give  earthy  carbonate  to  the  precipitate.  The  precipitate  holds 
the  paraffin  completely,  and  is  washed  on  the  filter  with  hot 
water,  drained  and  dried  at  100°  C.,  and  exhausted  with  petro- 
leum benzin  in  an  extraction  apparatus.  The  error  does  not 
overgo  0.3$  of  the  paraffin. 

BENEDIKT  (1886)  recommends  the  use  of  a  liquid  extraction 
apparatus  in  treating  the  aqueous  soap  solution  with  ether  or 
petroleum  benzin.  See  under  "Extraction  Apparatus  -  For 
Liquids,"  p.  38. 

Estimation  of  non-saponifiable  admixture  may  be  made  by 
calculation  of  the  Kdttstorfer's  number  (factor  of  saponification) 
(p.  254)  of  the  mixture  (a-^)  compared  with  that  of  the  pure 
saponifiable  fat,  as  known  (a).  Then  the  per  cent,  of  non-saponi- 

fiable  matter  (N)  =  100  —  12^. 

a 

Small  percentages  of  fat  in  mixture  with  hydrocarbons  may 
be  estimated  by  a  quantitative  determination  of  the  glycerin  re- 
sulting from  saponification,  using  the  permanganate- oxidation 
method.  (See  Glycerin,  f). 

Examination  of  the  non^saponifiable  matters. — Of  these  the 
ordinary  articles  are  as  follows:  Liquid — petroleum  .oils,  shale  oils, 


ESTIMA  TION  OF  FREE  FA  TTY  A  CIDS.        277 

tar  oils,  resin  oils ;  Solid — paraffin,  ceresin,  solid  fat  alcohols, 
cholesterin,  isocholesterin. — Of  the  tiqvids,  the  Mineral  Oils  from 
petroleum  and  from  shale  are  distilled  over  at  250°-300°  C.,  and 
of  sp.  gr.  0.855  to  0.900 ;  vaselin  oil  at  250°-350°  C.,  and  of  sp. 
gr.  0.900  to  0.930.— The  Tar  Oils  distilled  from  coal-tar  as  "  dead 
oils,"  from  240°  C.  to  350°  C.,1  purified  by  soda  lye,  are  used  as 
lubricating  oils,  and  have  sp.  gr.  above  1,  indeed  above  1.010. 
As  to  Rosin  Oils,  see  page  280.  Of  the  solids.  Paraffins  are 
white,  odorless,  of  sp.  gr.  0.869  to  0.943,  distil  without  change, 
are  graded  by  congealing  points  38°  to  82°  C.,  and  dissolve  in 
alcohol.  Ceresin  or  Ozokerite  is  not  distilled,  is  purified  by  sul- 
phuric acid,  and  agrees  in  general  with  paraffin  in  specific  gra- 
vities and  congealing  points. 

In  the  elaidin  test  the  mineral  oils  remain  nearly  or  quite 
unchanged. — Iodine  numbers  (p.  258)  distinguish  mineral  oils 
from  rosin  oils. — Glacial  acetic  acid,  100  grams,  at  50°  C.,  dis- 
solves 2.6  to  6.5  grams  of  various  mineral  oils;  about  17  grams 
rosin  oils.  In  determining  these  solubilities  2  c.c.  of  the  oil  to 
be  tested  may  be  treated  in  a  stoppered  test-tube  with  10  c.c. 
glacial  acetic  acid,  warming  in  a  water- bath  at  50°  C.  and  agitat- 
ing, filtering  through  a  filter  just  moistened  with  the  glacial  acid, 
and  determining  the  quantity  of  acetic  acid  in  a  weighed  portion 
of  filtrate  by  titrating  with  standard  alkali. — Acetone  is  used  for 
separation  of  mineral  oils  from  rosin  oils,  as  specified  under 
Rosin  Oils. — For  the  solid  non-saponifiable  matters  the  melting 
points  are  observed  (see  Melting  and  Congealing  Points  of  Solid 
Fats,  p.  271).  Treated  with  an  equal  weight  of  anhydrous  glacial 
acetic  acid,  boiling  some  time  with  a  return-condenser,  the  fat 
alcohols  (cetyl  alcohol,  etc.)  dissolve  completely,  cholesterin 
crystallizes  on  cooling,  and  paraffins  or  ceresins  swim  undis- 
solved  while  hot  and  congeal  on  cooling. 

Non  saponifictble  matters  (hydrocarbons  or  other  bodies)  in 
the  Fats  and  Waxes.  (ALLEN  and  THOMPSON,  1881.) — By  sapo- 
nification  and  extraction  with  petroleum  benzin  there  were 
found  of  unsaponifiable  matter — in  Lard,  0.23$  ;  Cotton-seed  oil, 
1.64$;  Olive  oil,  0.75$;  Rape  oil,  1.00$;  Cod-liver  oil,  1.32$ ; 
Japan  wax,  1.14$  ;  Spermaceti,  40.64$  ;  Beeswax,  52.38$  ;  Rosin 
oil,  98.72$  ;  Mineral  oils,  99.90$. 

ESTIMATION  OF  FREE  FATTY  ACIDS  IN  FATS.* — The  plan    of 

1  A  summary  of  the  fractions  of  coal-tar  distillation  is  given  under  Phenol. 

2GEissLEiC  1878:  Ding.  pol.  Jour.,  227,  92;  Zeitsch.  anal.  Chem.,  17,  393; 

Jour.  Chem.  Soc.,  34,  534.      BURSTYN,  1872.     HAGER,  1877.     WIEDERHOLD, 


278  FATS  AND  OILS. 

Geissler,  an  ethereal  solution  of  the  oil  being  titrated  with  stan- 
dard alcoholic  alkali,  to  the  neutral  reaction  of  phenol- phthalein, 
is  generally  applicable,  and  capable  of  variation  to  meet  techni- 
cal demands.  As  a  solvent  for  the  fats  and  oils,  ether  or  alcohol- 
ether  may  be  employed,  or  (GROGER)  5  to  10  parts  of  hot  alcohol 
may  be  used.  The  solvent  must  be  free  from  acidity.  Ether  is 
neutralized  for  this  purpose  by  adding  to  a  portion  a  drop  or 
two  of  phenol-phthalein  solution,  and  then  drops  of  alcoholic  al- 
kali, until  the  color  of  the  indicator  begins  to  appear  after  shak- 
ing. For  one  part  of  the  oil,  weighed  for  estimation,  2  or  3  parts 
of  ether  are  usually  sufficient.  The  alcoholic  alkali  solution  may 
be  made  with  good  alcoholic  potassa,  and  alcohol  free  from  fusel 
oil  (if  need  be,  filtered  through  animal  charcoal),  and  in  most 
cases  should  be  very  dilute,  approximately  20th  normal,  or 
weaker.  After  titrating  the  ethereal  solution  of  the  weighed 
quantity  of  the  oil,  with  the  alcoholic  alkali,  just  the  required 
quantity  of  this  is  again  taken  and  titrated  with  standard  acid. 
Generally  decinormal  acid  may  be  used,  or  a  solution  of  acid  in 
which  1  c.c.  corresponds  to  0.001  gram  of  the  fat  acid  under 
estimation.  It  is  better  to  express  the  results  in  percentages  of 
fatty  acids  in  the  fats  examined,  provided  a  representative  acid 
can  be  taken — as  n  per  cent,  of  free  acid  as  olew  acid.  BURSTYN'S 
numbers,  or  degrees  of  acidity  in  fats,  are  the  c.c.  of  normal  al- 
kali solution  neutralized  by  100  c.c.  of  fat ;  or  (KOTTSTORFER) 
100  grams  of  the  fat. 

ARCHBUTT  distils  a  mixture  of  the  oil  with  purified  methyl 
alcohol,  repeating  once,  and  titrates  the  distillate. 

Separation  of  Common  Resin  from  Fats  and  Soaps. — A 
satisfactory  method,  trustworthy  for  either  Quantitative  or  Quali- 
tative purposes,  is  that  of  GLADDING/  dependent  on  ether-solu- 
bility of  the  silver  salt,  and  corresponding  to  the  separation  of 
oleic  acid  by  ether-solubility  of  its  lead  salt.  Fatty  salts  of  silver 
are  insoluble,  resin  salt  of  silver  soluble  in  ether. — The  free  fat 
acids  are  to  be  obtained,  with  the  rosin,  neutral  fats  being  first 
saponified,  soaps  being  treated  with  acid,  and  the  total  free  fatty 
acids  washed  with  water  and  dried  if  need  be.  For  quantitative 
separation  the  directions  are  as  follows : 

About  0.5  of  the  fat  acids  is  accurately  weighed  into  a  small 
flask,  and  20  c.c.  of  95  per  cent,  alcohol  added  for  solution.  A 

1877.  KOTTSTORFER,  rancid  butters,  1879:  Zeitsch.  anal.  Chem.,  18,  436. 
GROGER,  1882:  Ding.  pol.  Jour.,  244,  307.  ARCHBUTT:  JKepert.  /.  anal. 
Chem.,  4,  330. 

1 1882:  Am.  Chem.  Jour.,  3,  416;  Jour.  Chem.  Soc.,  42,  663;  Chem.  News, 
45,  169;  Zeitsch.  anal  Chem.,  21,  585. 


SEPARA  TION  OF  RESIN.  279 

drop  of  phenol-plithalein  is  added,  then  a  saturated  alcohol  solu- 
tion of  caustic  potash  is  added  by  drops  until  the  color  of  an  alka- 
line reaction  is  obtained  after  agitation,  when  one  or.  two  drops 
of  the  alcoholic  potash  are  added  in  excess.  The  liquid  is  now 
held  at  the  temperature  of  boiling  alcohol  for  ten  minutes,  while 
the  flask  is  loosely  corked.  When  cold  the  contents  of  the  flask 
are  transferred  to  a  100  c.c.  graduated  cylinder,  rinsing  with  con- 
centrated ether,  and  diluting  with  this  solvent  just  to  the  100 
c.c.  mark.  The  cylinder  is  well  corked  and  shaken  for  a  mo- 
ment, and  about  1  gram  of  pure  silver  nitrate,  neutral  in  reaction, 
rubbed  to  an  impalpable  powder,  is  added  to  the  solution,  and 
the  whole  shaken  vigorously  for  10  or  15  minutes  until  the  pre- 
cipitate will  settle  clear.  The  volume  is  restored,  if  need  be,  to 
100  c.c.  by  adding  ether  and  shaking,  and  of  the  supernatent 
liquid  50  to  TO  c.c.,  as  an  aliquot  part  (m  c.c.)  ~bf  the  whole  100 
c.c.,  is  siphoned  off  by  means  of  a  slender  siphon  (previously 
filled  with  ether)  into  a  second  stoppered  100  c.c.  cylinder,  pass- 
ing the  liquid  through  a  small  filter  if  not  perfectly  clear.  The 
siphon  and  filter  are  rinsed  with  a  little  ether  into  the  second 
cylinder.  To  make  certain  that  the  silver  precipitation  is  com- 
plete, a  little  pulverized  silver  nitrate  is  shaken  up  with  the  clear 
liquid.  Now  a  mixture  of  7  c.c.  of  hydrochloric  acid  (sp.  gr. 
about  1.12)  and  14  c.c.  of  water  are  added,  and  the  whole  sha- 
ken vigorously  until  the  silver  is  wholly  converted  to  chloride. 
When  the  precipitate  has  settled  perfectly,  the  volume  (n  c.c.) 
of  the  ethereal  liquid  is  read,  and  an  aliquot  part  (p  c.c.)  of  this 
ethereal  solution  is  siphoned  off  into  a  tared  beaker,  rinsing  the 
siphon  into  the  beaker  with  a  little  ether,  and  the  ether  eva- 
porated gently,  to  obtain  the  weight  of  the  residue.  The  re- 
sidue is  the  resin,  representing,  through  both  the  aliquot  divi- 
sions, the  entire  resin  in  the  fat  taken.  A  small  but  nearly 
constant  proportion  of  oleic  acid  is  taken  up  as  silver  salt  by 
the  ether,  and  left  with  the  resin  in  the  final  residue  ;  therefore 
a  correction  is  made  as  follows:  for  every  10  c.c.  of  the  ethereal 
solution  of  silver  salt  siphoned  off,  0.00235  gram  is  deducted 
Then  having  w  as  the  number  of  grams  of  residue  obtained  in 
the  analysis,  and  a  as  the  number  of  grams  of  fat  taken  for 
analysis,  to  find  x  the  per  cent,  of  resin  in  the  fat  acids,  the  cal- 
culation is  as  follows  : 

10000  nw       2.35 

/y»     — —      _       _  — ___ 

am  o  a 

For  qualitative  purposes  the  same  operation,  performed  i., 
good,  strong  stoppered  cylinders  or  test-glasses,  without  weigh- 


280  FATS  AND  OILS. 

ing  or  measuring  portions,  will  give  trustworthy  results.  The 
final  residue  is  to  be  examined,  when  cold,  as  to  brittleness, 
solubilities,  etc.,  for  identification  of  resin  of  turpentine  or  com- 
mon rosin. 

ROSIN  OILS.  Resin  Oils.  Harzdle.1 — Of  complex  and  va- 
riable composition,  consisting  of  polymeric  terpenes  and  other 
hydrocarbons,  and  oxidized  bodies.  It  is  obtained  as  a  product 
of  the  destructive  distillation  of  common  resin  (resin  of  turpen- 
tine). 

Rosin  oils  are  known  by  specific  gravity  and  distillation  (&), 
by  sensible  properties  (b),  and  by  reactions  (d).  Separated,  in 
most  cases,  best  by  saponification  and  ether- solution  (e).  Found 
with  other  oils  (g). 

a. — A  liquid  of  a  brownish-yellow  color,  and  a  violet  to  blue 
fluorescence.  Sp.  gr.  0.96  to  0.99.  When  distilled  a  portion 
passes  over  below  250°  C.,  considerable  below  300°  C.,  and  al- 
most all  below  360°  C.  (REMONT).  The  lightest  fractional  distil- 
lates, when  obtained,  boil  at  103°  to  106°  C.,  and  from  light 
resin  oil  distillates  boiling  at  80°  C.  have  been  obtained.  Strong 
dextro-rotatory  powers  are  possessed  by  some  rosin  oils ;  others 
are  inactive,  still  others  levo-rotatory. 

b. — Rosin  oil  has  a  characteristic  taste,  and  an  odor  of  com- 
mon rosin,  the  odor  of  refined  rosin  oil  obtained  only  after 
heating. 

c. — Insoluble  in  water,  slightly  soluble  in  alcohol,  soluble 
in  all  proportions  in  ether,  chloroform,  carbon  disulphide,  pe- 
troleum benzin,  acetone,  petroleum  lubricating  oils,  essential  oils, 
and  glyceride  oils. 

d. — Not  saponifiable  (see  e). — Shaken  with  dry  stannous 
chloride,  or  better,  stannous  bromide  (ALLEN,  1884),  a  violet 
color  is  slowly  obtained. — Nitric  acid,  chlorine,  bromine  act 
as  oxidizing  agents,  with  uncertain  force,  sometimes  with  vio- 
lence. With  sulphuric  acid,  blackening  occurs.  The  vapor  burns 
with  a  smoky  flame. 

1  History  and  description:  REMONT,  1880-81:  Bull.  Soc.  Chim.,  |2],  33, 
461,  525;  Jour.  Ghent.  Soc.,  38,  683;  40,  202.  SCHAEDLER:  "Die  Technologie 
der  Fette  und  Oele  der  Fossillien,  sowie  der  Harzole  und  Schmeirmittel," 
1885-86,  Kapitel  xvi. — Composition:  TILDEN,  1880:  Ber.  d.  chem.  6fes.,  13, 
1604;  Jour.  Chem.  Soc.,  40,  101.  KELBE  and  WORTH,  1882:  Ber.  d.  chem. 
Ges.,  15,308.  RENARD,  1882:  Bull.  Soc.  Chim.,  [2],  36,  215;  Jour.  Chem. 
Soc,  42.  64. — Analysis:  DEMSKI  and  MORAWSKI,  1885:  Ding.  pol.  Jour.,  258, 
82;  Analyst,  10,  231. 


ROSIN  OILS.  281 

e. — Separation  of  rosin  oils  from  fixed  oils  by  distillation  is 
slow  and  imperfect,  but  may  yield  a  distillate  of  rosin  oil  suf- 
ficient for  identification  by  odor  and  other  properties. — Separa- 
tion from  glycerides  by  saponification  of  the  latter  is  more  satis- 
factory, but,  as  with  mineral  oils,  the  result  is  not  well  attained 
by  simple  aqueous  dilution  of  the  soap  solution.  Rosin  oils  are 
somewhat  soluble  in  strong  solutions  of  soap,  and  dilution  of  the 
solution  separates  fat  acid  from  the  soap.  Saponifying  with 
alkali  in  alcoholic  solution,  expelling  the  alcohol,  and  diluting 
with  water  short  of  turbidity  of  the  soap  solution  alone,  the 
liquid  is  shaken  out  with  portions  of  ether,  the  ether  evapo- 
rated from  the  ethereal  separate,  and  the  residue  tested  by  odor 
when  hot,  by  taste,  by  stannous  chloride,  and  by  gravity,  for 
rosin  oil. 

Separation  from  Mineral  Oils  by  acetone  as  a  solvent  is  done 
as  follows  (DEMSKI  and  MORAWSKI,  where  cited).  Rosin  oils  dis- 
solve in  all  proportions  of  acetone.  50  c.c.  of  the  sample  of 
oil  are  shaken  up  several  times  with  25  c.c.  of  acetone  in  a  100 
c.c.  graduated  cylinder,  and  then  left  at  rest  for  some  time.  If 
the  liquid  separates  into  two  layers,  10  c.c.  of  the  upper  are 
drawn  off,  and  the  amount  of  oil  in  it  determined  after  evapora- 
tion of  the  acetone.  The  density  of  this  residue  is  judged  by 
adding  water  to  a  few  drops  of  it,  and  then  alcohol  until  the  oil 
just  begins  to  sink.  Finally  it  is  required  to  determine  the 
amount  of  rosin  oil  which  it  is  necessary  to  add  to  the  sample  of 
oil  under  examination  to  enable  it  to  dissolve  in  half  its  volume 
of  acetone.  As  soon  as  perfect  solution  is  effected  the  liquid 
gives  a  fairly  permanent  froth  when  shaken.  With  American 
mineral  oils  35$  of  rosin  oil  is  at  once  detected  by  its  solubility 
in  acetone ;  with  Caucasian  and  Wallachian  oils  50$  is  at  once 
detected. 

g. — Rosin  oils  are  used  legitimately  for  lubricating  purposes. 
As  adulterants  they  have  a  wide  distribution,  in  lubricating  oils, 
in  linseed  oil,  olive  oil,  and  even  in  castor  oil  and  the  essen- 
tial oils. — Rosin  Grease  is  a  saponaceous  paste  made  by  mixing 
slaked  lime  with  rosin  oil. 

DRYING  AND  NON-DRYING  OILS,  DISTINCTIONS  BETWEEN. — (1) 
Elaidin  Test.  The  action  of  fuming  nitric  acid,  or  of  nitric 
acid  with  metallic  copper  or  metallic  mercury,  or  the  action  of 
a  concentrated  solution  of  mercuric  nitrate,  in  warm  digestion, 
noting  the  result  each  quarter  of  an  hour,  and  later  each  hour. 
Non-drying  oils  are  converted  into  a  solid  mass,  termed  elaidin, 


282 


FATS  AND  OILS. 


a  glyceride  of  elaidic  acid  (p.  247),  which  is  isomeric  with  oleic 
acid.  The  reaction,  therefore,  is  not  an  oxidation,  though  ef- 
fected by  an  oxidizing  agent. 

(2)  Warming  effect  of  Sulphuric  Acid  (MAUMENE,  1881 ;  AL- 
LEN, 1881 ').  The  sulphuric  acid  should  be  anhydrous.  It  may 
be  prepared  by  heating  to  320°  C.,  and  cooling  to  the  tempera- 
ture of  the  oil.  Of  the  concentrated  acid  10  c.c.  are  taken  in  a 
beaker,  and  50  grams  of  the  oil  are  added,  when  the  mixture  is 
slowly  stirred  with  the  thermometer  bulb  until,  after  rising, 
the  thermometer  begins  to  fall,  when  the  degree  is  noted,  the 
initial  temperature  of  the  oil  and  acid  is  subtracted,  and  the 
elevation  of  temperature  obtained. 


ELEVATION  OI 

"•    TEMPERATURE. 

Maumene. 

Paris  City 
Laboratory. 

Non-drying  : 
Olive  oil  

42°  C. 

51-55.5°  C. 

Peanut  oil  . 

62 

Cotton-seed  oil  

69.5 

Sweet-almond  oil  

53.5 

Beechnut  oil  

65 

Castor  oil  

47 

Sheep-foot  oil  

51.5 

Olein  (oleic  acid)  of  saponification.  . 
Drying  : 
Poppy.  . 

70.5 

47.5 
73 

TT  rr<; 
Hemp  

98 

Walnut  

101 

Linseed  

133 

114.5 

Train  oils  : 
Cod-liver  oil  

103 

"          "  brown 

89.5 

Sperm  oil.  . 

63  5-73 

(3)  Iodine  numbers.     The  fat  acids  of  the  drying  oils  have  a 


'A.  H.  ALLEN,  Analyst,  6,  102. 


DRYING  AND  NON-DRYING  OILS. 


283 


freater  capacity  for  iodine  combination  than  the  non-drying  oils, 
ee  pp.  258,  259. 

(4)  Oxygen-absorption.  The  greater  the  "  drying  "  capacity 
of  an  oil,  the  more  oxygen  it  absorbs  on  a  given  exposure  to  air. 
Precipitated  metallic  lead  is  added  to  favor  oxidation  and  enable 
a  measure  of  the  oxidation  to  be  made  (LIVACHE,  1883  ').  The 
lead  is  prepared  by  precipitating  lead  acetate  solution  with  zinc, 
at  once  washing  the  precipitate  with  a  little  water,  then  with  al- 
cohol, then  with  ether,  and  drying  in  a  vacuum.  In  a  large  tared 
watch-glass  one  gram  of  the  lead  is  taken,  and  from  0. 6  to  0.  T 
gram  of  the  oil  is  dropped  slowly  upon  the  lead,  and  the  weight 
of  all  taken,  giving  the  weight  of  oil.  The  test  is  set  aside,  at 
medium  temperature,  in  a  place  free  from  vapors  or  dust,  and 
the  weight  taken  after  18  hours,  to  4  or  5  days,  or  longer. 


INCREASE   ( 

)F   WEIGHT. 

OF  THE   FAT 
ACIDS. 

After  2  days. 

After  7  days. 

After  8  days. 

Linseed  oil  

143* 

\\% 

Walnut  oil  

7.9 

6 

Poppy  oil  . 

6.8 

3.7 

Cotton-seed  oil  

5.9 

0.8 

Beechnut  oil  

4.3 

2.6 

Colza  oil  

0.0 

2.9$ 

2.6 

Rape  oil  

0.0 

2.9 

0.9 

Olive  oil  

0.0 

1.7 

0.7 

Oxygen-absorption  has  been  studied  by  "W.  Fox,2  who  de- 
termines the  oxygen  absorbed  by  direct  estimation.  About  1 
fram  of  the  oil  is  sealed  in  a  tube  of  100  c.c.  capacity,  or  5  or 
drops  of  the  oil  (weighed)  are  placed  in  a  well-ground,  stop- 
pered flask  of  200  c.  c.  capacity ;  the  whole  heated  in  an  oil-bath 
at  104. 5°  C.  (220°  F.)  for  about  four  hours;  the  tube  or  flask 
opened  under  water,  the  remaining  gas  measured  in  a  eudio- 
meter, also  the  remaining  oxygen  estimated  by  pyrogallol  and 
potash,  using  the  precautions  and  -corrections  of  gas  analysis, 
for  estimation  of  the  quantity  of  oxygen  gas  taken  up  by  the 
weighed  quantity  of  oil. — The  author  flnds  that  avidity  for  oxy- 


i  C'>mpt.  rend.,  97,  1311;  Jour.  Gh"m  Sor.,  46,  532. 
3  1883:  Analyst,  8, 116;  New  Bern.,  12,  367. 


284  FATS  AND  OILS. 

gen  is  influenced  largely  by  presence  of  fat  acids  formed  by 
standing  open  to  the  air,  and  that  the  differences  thus  due  to 
age  and  exposure  are  removed  by  heating  the  oil  to  204°  C. 
(400°  F.) — The  author  holds  the  value  of  lubricating  oils  to  be 
largely  dependent  on  their  non-absorption  of  oxygen.  Also,  he 
claims  that  his  method  gives  the  surest  detection  of  cotton-seed 
oil  in  admixture  with  olive  oil.  He  gives  the  following  results 
in  c.c.  of  oxygen  absorbed:  Linseed  oils — Baltic  Sea.  191 ;  Black 
Sea,  186  ;  Calcutta,  126  ;  Bombay,  130  ;  American,  156.  Cotton- 
seed  oil,  refined,  24.6;  rape-seed  oil,  brown,  20;  rape-seed  oil, 
colza,  17.6.  Olive  oil,  highest,  8.7;  lowest,  8.2. 

LINSEED  OiL.1 — Leinol.  Huile  de  lin.  Flachsol.  Chiefly  the 
triglyceride  of  Linoleic  Acid  (p.  249),  C3H5(C16H2?O2)3— 794.— 
A  lixed  oil  expressed  from  flaxseed,  the  seed  of  Linum  usitatis- 
simum,  of  which  it  should  form  as  much  as  25  per  cent. 

See  Drying  and  Non-drying  Oils,  under  Fats,  p.  281. 

a.— A  yellowish  or  yellow  oily  liquid,  of  the  sp.  gr.  about 
0.936  (II.  S.  Ph.),  at  15°  C.  0.9347  (SCHUBLER),  0.9325  (Sou- 
CHERE),  0.930-0.935  (ALLEN).  Specific  gravity  of  the  total  fat 
acids,  at  100°  C.,  0.8599  (ARCHBUTT  and  ALLEN).  Congeals  at 
— 16°  C.  after  a  few  days  (GussEROw) ;  —  27°  C.  (CHATEAU). 
Melts  at  —16°  to  —20°  (GLASSNER).  The  total  fat  acids  con- 
geal at  13.3°  C.  (HUBL)  ;  melt  at  17.0°  (HUBL).  Boiled  Linseed 
Oil  has  sp.  gr.  0.940-0.941. 

£. — Linseed  oil  has  a  slight  peculiar  odor  and  a  bland  taste. 

c. — Insoluble  in  water ;  soluble  in  5  parts  absolute  alcohol, 
in  1.5  parts  ether. 

d. — Linseed  oil,  treated  with  nitrous  acid,  does  not  yield 
elaidin.  Mixed  with  concentrated  sulphuric  acid,  as  directed 
under  Drying  and  Non-drying  Oils,  Distinctions  between,  p.  282, 
very  high  numbers  are  obtained.  Treated  with  iodine,  large  ab- 
sorption capacity  is  found  (pp.  258  and  259).  For  oxygen-ab- 
sorption see  Drying  Oils,  etc.,  p.  283. 

e,  f. — For  Separation  and  Valuation  of  Linseed  oil,  see  Dry- 
ing Oils,  p.  281,  and  Linoleic  Acid,  p.  249. 

gt — Linseed  oil  is  adulterated  with  cotton-seed  oil,  mineral 

1  Schaedler:  "Technologie  der  Fette  und  Oele,"  1883,  p.  494.  Benedikt, 
"  Analyse  der  Fette,"  1886,  p.  215. 


OLIVE  OIL.  285 

oils,  rosin  oil,  niger-seed  oil,  rape-seed  oil,  hemp-seed  oil,  and  fish 
oils.  Mustard,  rape,  and  hemp  seeds  are  gathered  with  flax-seed. 
Specific  gravity  of  mineral  oils  is  lighter  than  of  linseed  oil,  usu- 
ally from  0.880  to  0.905  ;  while  resin  oil  is  heavier,  0.96  to  0.99. 
Non  drying  oils  are  indicated  by  the  elaidin  test,  by  not  generat- 
ing the  full  quota  of  heat  with  sulphuric  acid,  by  not  absorbing 
the  proper-amount  of  oxygen,  and  by  lower  iodine  numbers,  ac- 
cording to  directions  given  under  Drying  Oils,  p.  281.  Presence 
of  hydrocarbon  or  mineral  oils  is  shown  by  their  non-saponifica- 
tion,  sometimes  revealed  by  fluorescence,  and  sometimes  by  distil- 
lation, as  specified  under  Separation  of  Mineral  Oils  from  Fat 
Oils,  p.  274.  Examination  for  Rosin  Oil  is  directed  under  the 
latter,  p.  281. 

Boiled  Linseed  Oil  is  prepared  by  exposure  to  a  high  tempe- 
rature, by  which  it  undergoes  oxidation  and  acquires  increased 
readiness  for  oxidation.  Dryers  are  added,  also,  in  the  "  boiling," 
to  promote  oxidation  by  the  atmosphere.  Manganese  and  lead 
oxide,  used  as  dryers,  leave  traces  of  these  metals  in  the  oil,  so 
that  they  may  be  detected  in  the  ash. 

Boiled  linseed  oil  is  frequently  adulterated  with  a  very  little 
rosin  and  with  rosin  oil. 

OLTVE  OIL. — The  fixed  oil  expressed  from  the  fruit  of  Olea 
europoe  i.  Olivenol,  Baumol.  "  Sweet  oil."  Among  the  best 
are  .Provence  oil  and  Florence  oil.  Lucca  and  Gallipoli  oils  are 
good  brands.  Sicily  oil  is  seldom  of  best  quality.  Olive  oil  is 
adulterated  and  substituted  by  cotton-seed  oil,  rape  oil,  poppy 
oil,  sesame  oil,  peanut  oil. 

a. — A  pale  yellow,  or  light  greenish-yellow,  oily  liquid,  of 
,sp.  gr.  0.915  to  0.918  (U.  S.  Ph.  and  Pli.  Germ.)  At  15°  0., 
best  0.9178  ;  Gallipoli,  0.9196  (CLAKK)  ;  0.914  to  0.917  (ALLEN). 
At  18°  C.,  yellow  green  0.9144,  dark  0.9199  (STILURELL).  Spe- 
cific gravity  of  the  fat  acids,  at  100°  C.,  0.8429-0.8444  (ARCH- 
BUTT).— Congealing  point,  turbid  at  2°  C  ,  solid  at  —6°  C.  Of  the 
fat  acids,  congealing  point  21.2°  C.,  melting  point  26°  C. 
(HUBL)  ;  congealing  point  not  under  22°  C.,  melting  point 
26.5  to  28.5°  C.  (BACH). 

£.  — Of  a  nutty,  oleaginous,  and  faintly  acrid  taste,  and  nearly 
without  odor. 

G. — Sparingly  soluble  in  alcohol,  readily  soluble  in  ether. 

g. — Tests  for  purity. — "  If  1  part  of  olive  oil  be  agitated  in 
a  test-tube  with  2  parts  of  a  cold  mixture  prepared  from  equal 


286 


FA  TS  AND  OILS. 


volumes  of  strong  sulphuric  acid  and  of  nitric  acid  of  sp.  gr. 
1.185,  and  the  mixture  be  set  aside  for  half  an  hour,  the  super- 
natent,  oily  layer  should  not  have  a  darker  tint  than  yellowish 
(a  dark  color  indicating  the  presence  of  other  fixed  oils).  If  12 
parts  of  the  oil  be  shaken  frequently  during  two  hours  with  1 
part  of  a  freshly-prepared  solution  of  6  grams  of  mercury  in  7.5 
grams  of  nitric  acid  (sp.  gr.  1.40),  a  perfectly  solid  mass  of  a 
pale  straw  color  should  result ;  and  if  1  gram  of  the  oil  be  shaken 
for  a  few  seconds  with  1  gram  of  a  cold  mixture  of  sulphuric 
acid  (sp.  gr.  1.830)  and  nitric  acid  (sp.  gr.  1.250),  and  1  gram  of 
disulphide  of  carbon,  no  green  or  red  layer  should  separate  on 
standing.  If  5  drops  of  the  oil  are  let  fall  upon  a  thin  layer  of 
sulphuric  acid  in  a  flat-bottomed  capsule,  no  brown-red  or  dark 
zone  should  be  developed  within  three  minutes  at  the  line  of 
contact  of  the  two  liquids  (absence  of  appreciable  quantities  of 
other  fixed  oils  of  similar  properties)." — U.  S.  Ph. 

"  At  about  10°  C.  it  begins  to  grow  turbid  by  crystallization, 
at  0°  C.  acquires  a  salve-like  thickness.  When  5  grams  of  the 
oil  are  shaken  with  15  drops  of  nitric  acid  of  sp.  gr.  1.38,  neither 
the  acid  nor  masses  swimming  upon  it  should  take  a  red  color. 
Fifteen  parts  of  olive  oil  which  have  been  strongly  shaken  with 
a  mixture  of  2  parts  water  and  3  parts  of  fuming  nitric  acid 
should  form  a  whitish  mass,  not  red  nor  brown,  separating  in  1  or 
2  hours  in  a  solid  mass,  while  the  liquid  is  scarcely  colored." 
—Ph.  Germ. 

"  Pale  yellow  or  greenish-yellow,  with  a  very  faint,  agreeable 
odor,  and  a  bland,  oleaginous  taste ;  congeals  partially  at  about 
36°  F.  (2.2°  C.)  "— Br.  Ph. 

Specific  gravity  of  mixtures  of  Olive  oil  with  stated  percentages 
of  other  oils,  at  15°  C.  (SOUCHERE,  1881,  using  Lefebre's 
Oleometer) : 


Name  of  the  oil. 

Sp.  gr.  of 

the  oil 
admixed. 

IQperct. 

20perct. 

SO  per  ct. 

40  per  ct. 

50  per  ct. 

Olive  

0.9153 

Colza.   . 

0  9142 

0  91519 

0  91508 

0  91497 

0  91486 

0  91475 

Sesame  
Cotton-  seed.  . 
Walnut  

0.9225 
0.9230 
0.9170 

0.91602 
0.91607 
0  91547 

0.91674 
0.91684 
0  91564 

0.91741 
0.91761 
0.91581 

0.91818 

0.91838 
0.9159S 

0.91890 
0.91915 
0.91615 

cRSITY 


OF 


TURKEY-RED  OIL.— COTTON-SEED  OIL.       287 

Congealing  and  Melting  points  of  Fat  Acids  of  Olive  oil  with 
stated  percentages  of  fat  acids  of  other  oils  (JDACH,1  1883) : 


Fat  acids  from 

Congealing  at 

Melting  at 

Pure  olive  oil.  .                  .        . 

Above  22°  C. 

26  5-28  5°  C 

Olive  oil  with  20$  cotton-seed 
oil  

28° 

31  5° 

Olive  oil  with  20$  sunflower- 
seed  oil  

18 

24 

Olive  oil  with  33^$  rape-seed 
oil  

16.5 

23  5 

Cotton-seed  oil,  alone 

35  0 

38  0 

Castor  oil,  alone  ..... 

2  0 

13  0 

TURKEY-RED  OIL. — A  thoroughly  non-drying  oil  suitable  for 
technical  ^use  in  dyeing  cotton  turkey-red.  Grades  of  olive  oil 
have  generally  been  used.  Partly  unripe  olives,  macerated  in 
boiling  water  before  being  pressed,  yield  an  oil  rich  in  extractive 
matter  and  favorable  for  this  use.  In  the  elaidin  test  a  solid 
and  firm  elaidin,  of  white  color,  should  be  obtained. 

OLIVE-KEKNEL  OIL. — From  the  kernel  or  nut  of  the  olive,  by 
pressure,  or  extraction  with  carbon  disulphide.  Distinguished 
from  olive  oil  by  its  dark  greenish-brown  color  and  a  quite  free 
solubility  in  alcohol  or  glacial  acetic  acid. 

COTTON-SEED  OIL.' — Baumwollensamenol  or  Baumwollenol. 
Huile  de  Coton.  Oleum  gossypii  seminis. — A  fixed  oil  ex- 
pressed from  the  seed  of  species  of  Gossypium.  The  crude  oil 
contains  as  much  as  15  pounds  of  color  substance  per  ton  (LONG- 
MORE).  The  color  substance,  termed  gossypin,  is  soluble  in  alka- 
lies, and  from  alkaline  solution  precipitated  by  acids.  Treatment 
with  soda  lye  of  five  or  six  per  cent,  at  60°  F.  is  adopted  in  puri- 
fication of  the  oil,  only  a  small  part  of  which  saponifies.  The 
soapy  mixture  containing  the  color,  when  digested  with  strong 
soda  lye  and  then  neutralized  with  sulphuric  acid,  yields  a  pre- 
cipitate of  the  gossypin. 

1  Chemiker-Zeitung,  7,  356  ;   Zeitsch.  anal.  Chem.,  23,  259  ;   Am.  Jour. 
Phar.,  55,  354. 

2  Production,  Uses,  and  Properties,  C   S.  Munroe,  1885:  Am.  Chem.  Review, 
5,  23.     Purification,  J.  Longmore,  1886:  Jour.  Soc.  Chem.  Industry. 


288  FATS  AND  OILS. 

a. — The  crude  oil  is  a  thick,  brownish,  turbid  liquid,  which 
deposits  a  slimy  residue.  The  clarified  oil  is  clear  orange  yel- 
low ;  better  purified  grades  light  yellow.  Fully  refined  cotton- 
seed oil  is  of  a  very  pale  straw  color. — Sp.  gr.,  at  15°  C., 
0.922-0.930  (ALLEN);  0.9228  (VALENTA)  ;  at  17°  C.,  0.923 
(SCHEIBE);  at  18°  C.,  crude  oil  0.9224,  refined  oil  0.9230,  white 
oil  0.9288  (STILUEELL).  Sp.  gr.  of  the  fat  acids  at  100°  C., 
0.849  (AROHBUTT). — Congeals  to  deposit  stearin  at  12°  C. ; 
solidifies  fully  at  0°  to  —1°  C.  The  fat  acids  congeal  at  30.5°  C. 
(HiiBL),  at  35.0°  C.  (BACH),  at  35.5°  C.  ( YALENTA)  ;  melt  at 
35.2°  C.  (ALLEN)  ;  begin  to  melt  at  39°-40°  C.,  melt  wholly  at 
42°-43°  C.  (BENSEMAN). 

&. — The  well-refined  oil  has  only  a  slight  earthy  odor,  and  a 
bland,  perceptibly  nutty  taste. 

c. — Solubility  in  glacial  acetic  acid,  according  to  Valenta,  is 
stated  at  p.  273,  and  furnishes  a  distinction  from  olive  oil. 

d. — Stirred  with  potassium  hydrate  solution,  crude  cotton- 
seed oil  colors  blue  in  the  upper  layer,  becoming  violet  on  expo- 
sure to  the  air.  The  same  colors  are  developed  on  saponifying 
with  alcoholic  potassa,  but  are  hardly  made  perceptible  with  the 
most  fully  refined  oil. — When  a  drop  of  sulphuric  acid  is  added 
to  a  larger  quantity  of  unrefined  oil,  bright  red  to  brown  colora- 
tion is  produced.  The  test  is  better  made  with  near  equal  quan- 
tities of  oil  and  sulphuric  acid  of  sp.gr.  1.76,  gently  warming 
the  mixture  after  observing  the  first  effect.  The  refined  oil  re- 
sponds very  slightly  to  this  test. — In  the  elaidin  test  cotton-seed 
oil  gives  elaidin,  with  reddish-yellow  to  brownish-yellow  colors, 
these  tints  being  obtained  also  with  nitric  acid  of  sp.  gr.  1.42 
added  in  equal  volume.  — Silver  nitrate  in  ether-alcoholic  solu- 
tion is  gradually  reduced,  with  dark  colors,  but  t.  lis  is  in  a  de- 
gree common  to  seed  oils  and  olive  oil.  BECHI  (1885)  uses  a 
\%  solution  of  silver  nitrate  in  strong  alcohol,  adding  5  c.c.  of  this 
solution  to  a  mixture  of  25  c.c.  alcohol  and  5  c.c.  of  the  oil,  and 
warming  to  84°  C.,  when  olive  oil,  he  states,  does  not  color  if  cotton- 
seed oil  be  absent. — Cotton-seed  oil  contains  about  1.64$  of  non- 
saponifiable  matter  (ALLEN  and  THOMPSON,  RODIGER).  By  full 
saponification  and  extraction  of  the  dry  soap  with  petroleum 
benzin  (p.  275)  a  distinction  from  olive  oil  is  obtained. 

Cotton-seed  oil  is  a  very  feebly  drying  oil.  For  its  identifi- 
cation, and  distinction  from  olive  >il,  by  this  property,  tests  are 
made  by  oxygen-absorption  (p.  283),  wanning  effect  of  sulphuric 
acid  (p.  282),  and  the  iodine  numbers  (p.  258).  Its  separate  fat 


COTTONSEED  STEARIN.— CASTOR  OIL.       289 

acids,  in  the  oxygen-absorption  test,  unlike  the  entire  oil,  rank 
with  wholly  non-drying  oils. 

The  high  melting  and  congealing  points  of  the  fat  acids  of 
cotton-seed  oil  distinguish  it  from  most  other  similar  oils  (&,  and 
pp.  265,  269). 

Distinctions  between  cotton-Seed  oil  and  olive  oil  are  further 
given  under  the  head  of  the  latter,  p.  285.  The  saponification 
numbers  of  olive  oil  and  cotton-seed  oil  are  too  near  each  other 
to  furnish  a  means  of  distinction. 

COTTON  SEED  STEARIN. — Baumwollenstearin.  Vegetable  Mar- 
garin.  Vegetable  Stearin. — The  residue  of  cold-pressed  cotton- 
seed oil.  A  sample  examined  by  MUTER  had  sp.  gr.  0.9115-0.912 
at  37.7°  C.  (100°  F.),  and  gave  95.5$  insoluble  fat  acids,  perfectly 
soluble  in  hot  absolute  alcohol  as  well  as  in  ether.  The  melting 
point  was  32.2°  C.,  the  melted  liquid  having  a  yellow  color  and 
odor  of  cotton-seed  oil.  It  congealed  again  at  about  1°  C.  A 
sample  examined  by  Mayer  melted  at  39°  C. 

CASTOR  OIL.  — Oleum  Ricini.  Kicinusol.  Huile  de  ricin, 
de  castor. — A  fixed  oil  expressed  from  the  seed  of  the  Ricinus 
communis.  See  Ricinoleic  Acid,  of  which  it  is  in  chief  part  the 
glyceride,  p.  248.  Eiciiiolein  is  C3H5(C18H3303)3  =  931. 

a. — "An  almost  colorless,  transparent,  viscid  liquid;  of  sp. 
gr.  0.950-0.970."— U.  S.  Ph.  Sp.  gr.  at  15°  C.,  0.9613-0.9736 
(VALENTA);  at  18°  C.,  0.9667  (STILURELL)  ;  at  23°  C.,  0.964 
(DIETERICH).  Congeals  at  — 10°  to  — 18°  C.  Fat  acids  congeal  at 
3°  C.  ;  melt  at  13°  C.  (HiiBL).  "  When  cooled  it  becomes  thicker, 
generally  depositing  white  granules,  and  at  about  — 18°  C. 
(0.4°  F.)  it  congeals  to  a  yellowish  mass." — U.  S.  Ph. 

b.  —  "Of  a  bland,  afterwards  slightly  acrid  and  generally  of- 
fensive taste,  and  a  faint,  mild  odor." — tl.  S.  Ph. 

£.__«  Soluble  in  an  equal  weight  of  alcohol  [0.820  at  15  6° 
C.]  and  in  all  proportions  of  absolute  alcohol  or  glacial  acetic 
acid."— U.  S.  Ph.  At  15°  C.  in  2  parts  90$,  and  in  4  parts 
84$  alcohol.  Not  soluble  in  petroleum  benzin,  kerosene,  or 
paraffin  oil,  but  dissolves  about  one  and  a  half  volumes  of  kero- 
sene or  paraffin  oil.  The  solubility  in  alcohol  is  much  varied  by 
temperature. 

d.  —Castor  oil  is  to  a  very  slight  extent  a  drying  oil.  Expo- 
sure to  air  causes  it  to  become  perceptibly  thicker.  In  the  heat- 
ing effect  of  sulphuric  acid  (p.  282),  and  in  the  iodine  number  of 


290  FA  TS  AND  OILS. 

the  oil  or  its  acid  (p.  258),  castor  oil  stands  not  far  from  olive 
oil.  It  gives  the  elaidin  reaction.  Its  saponifieation  number  is 
comparatively  low  (p.  257). 

g. — Impurities  and  substitutions. — The  solubilities  in  alco- 
hol and  in  glacial  acetic  acid,  quoted  under  c  from  the  U.  S.  Ph., 
furnish  a  generally  satisfactory  means  of  revealing  impurities. 
The  absorption  of  a  little  petroleum  benzin  has  been  used  by 
Hager  for  detection  of  adulterations  as  follows  :  One  volume  of 
the  oil  is  agitated  in  a  test-tube  with  2  volumes  of  the  benzin, 
and  set  aside.  The  lower  layer  should  be  increased  to  from  1.6 
to  1.75  of  the  original  volume  of  the  castor  oil.  In  case  of  adul- 
teration the  lower  layer  will  be  proportionally  deficient. 

Under  direction  of  the  New  York  State  Board  of  Health,  in 
1881,  Prof.  G.  C.  Caldwell '  examined  16  samples,  of  which  9 
were  considered  adulterated,  1  with  sesame  oil,  4  with  cotton-seed 
oil,  2  with  peanut  oil,  and  2  with  cotton-seed  oil  or  peanut  oil  or 
both.  While  giving  a  caution  against  dependence  upon  single 
tests  (not  thoroughly  subjected  to  control  analyses),  Prof.  Cald- 
well advises  the  legal  adoption  of  test  limits. 

LARD. — Adeps.  Schweinschmalz.  Graisse  de  pore.—'4  The 
prepared  internal  fat  of  the  abdomen  of  Sus  scrofa,  purified  by 
washing  with  water,  melting,  and  straining." 

a  —A  soft,  white,  unctuous  solid,  of  sp.  gr.  about  0.938 
(U.  S.  Ph.)  at  15°  C.;  at  100°  C.  (water  at  15°  =  1)  0.861  (Ko- 
NIGS).  Melts  at  or  near  35°  C.  (U.  S.  Ph.),  42°-48°  C.  (KoNiGs). 
At  26°  C.  melted  lard  begins  to  congeal,  and  during  congelation 
the  temperature  rises  to  30°  C.  (SCHAEDLER).  The  fat  acids 
melt  at  35°  C.,  and  congeal  again  at  34°  C.  (MAYER).— When 
rancid,  lard  acquires  a  yellowish  color. 

I.—  Lard  when  fresh  and  good  has  a  faint  odor  free  from 
rancidity,  a  bland  taste,  and  a  neutral  reaction.  In  the  air  it 
soon  becomes  rancid  and  of  an  acid  reaction. 

c. — It  is  entirely  soluble  in  ether,  petroleum  benzin,  and 
disulphide  of  carbon. 

^  e^  y.__The  saponification  number  of  Kottstorfer,  for  lard, 
is  195.8  ;  195.3-196.6  (YALENTA).  The  iodine  number  of  Hubl, 
59.0.  The  per  cent,  of  insoluble  fat  acids  (Hehner's  number), 
96.15  (WEST-KNIGHTS)  ;  of  non-saponifiable  matter,  0.23  (ALLEN 
and  THOMPSON).  The  per  cent,  of  olein  is  given  by  BRACONNOT 

1  Analyst,  7,  97;  from  Sanitary  Engineer. 


LARD.  291 

at  62  ;  by  calculation  from  the  iodine  number,  68.4.  The  melt- 
ing and  congealing  points  of  the  fatty  acids  are  named  under  a. 
See  Fat  Acids,  Quantitative  Determination  of,  (1)  to  (9),  pp.  250, 
274. 

g. Impurities. — Of  these  the  most  common  is  dilution  with 

water,  either  with  or  without  lime,  alum,  or  other  adjuvant, 
forming  "  watered  lard  " ;  and  those  next  most  probable  in  this 
country  are  "  cotton  stearin  "  (p.  289),  and  mixtures  of  tallow  or 
tallow  stearin  with  cotton-seed  oil.  C  >  <,unut  oil  has  also  been 
used. 

"  Distilled  water,  boiled  with  lard,  should  not  acquire  an  al- 
kaline reaction  (absence  of  alkalies),  nor  should  a  portion  be 
colored  blue  by  iodine  (absence  of  starch).  A  portion  of  the 
water,  when 'filtered,  acidulated  with  nitric  acid,  and  treated  with 
test  solution  of  nitrate  of  silver,  should  not  yield  a  white  preci- 
pitate soluble  in  ammonia  (absence  of  common  salt).  When 
heated  for  several  hours  on  the  water-bath,  under  frequent  stir- 
ring, lard  should  not  diminish  sensibly  in  weight  (absence  of 
water)."— U.  S.  Ph. 

"  Hot  alcohol  shaken  with  the  lard,  and  when  cold  diluted 
with  an  equal  part  of  water,  should  not  affect  litmus-papers. 
When  2  parts  of  the  lard  are  boiled  with  2  parts  of  (15#)  potash 
solution  and  1  part  of  alcohol,  until  the  mixture  becomes  clear, 
and  evaporated  over  the  water-bath,  the  residual  soap  should  dis- 
solve in  15  parts  of  warm  water  on  the  addition  of  10  parts  of 
alcohol."— Ph.  Germ 

Dr.  MUTER,  in  1882,1  made  report  to  the  Public  Analysts  of 
a  sample  of  lard  adulterated  with  "cotton  stearin,"  of  density  of 
0.912  as  a  liquid  at  37.8°  C.  (100°  F.);  yielding  95.5$  fat  acids 
all  insoluble,  and  requiring  some  time  to  solidify  at  4.4°  C.  (40° 
F.)  The  high  density  was  the  obvious  indication  that  it  was 
not  lard  alone.  The  sample  represented  a  grade  appearing  on 
the  market. — Alleged  adulteration  of  "  prime  steam  lard"  with 
cotton-seed  oil  products,  in  Chicago  in  1883,  was  made  the  occa- 
sion of  a  protracted  trial  before  the  Board  of  Trade  of  the  City 
of  Chicago.2 

1  Analyst,  7,  93: 

2  The  evidence  of  a  good  number  of  American  chemists  in  this  case,  with 
proceedings  and  findings,  was  published  by  the  Board  of  Trade:  "McGeoch, 
Everinghain  &  Co.  vs.  Fowler  Brothers,"  pp.   280,  1883,  Chicago.     Samples 
of  known  admixture  of  lard  with  tallow,  lard  with  cotton-seed  oil,  and  of  pure 
lard  were  submitted  to  four  chemists  and  to  one  microscopist  for  analysis. 
The  reports  were  not  in  accord  with  each  other,  and  to  a  great  extent  failed  of 
their  object.     A  method  of  separation  by  use  of  alcohol-ether  as  a  solvent  was 


292  FATS  AND   OILS. 

Respecting  Microscopical  Examination  of  lard  and  other  fats, 
Dr.  J.  H.  LONG  has  contributed  a  valuable  summary,1  with  origi- 
nal micro-photographs. 

LAKD  OIL. — Schmalzol.  Speckol. — By  pressure  of  lard  at 
about  0°  C.,  the  residue  being  the  Solar  Stearin  or  Lard  Stearin 
of  the  candle  industry.  Sp.  gr.  of  lard  oil,  0.915  (ALLEN).  Sa- 
ponification  number,  191-196  (MOORE). 

TALLOW  OIL.  Talgol.— By  pressure  of  tallow  at  low  tempe- 
ratures, much  lower  than  are  employed  for  oleomargarin. 

OLEOMABGARIN. — This  term  has  been  primarily  applied  to  a 
product  of  purified  fresh  tallow  with  rejection  of  a  good  part  of 
its  stearin.  The  invention  of  Hippolyte  Mege,  of  Paris,  France, 
prescribed  that  fresh  suet  should  be  immersed  in  a  brine  of  com- 
mon salt  and  sodium  sulphite  or  other  addition,  then  crushed  be- 
tween rollers  and  washed,  and  digested  at  103°  F.  (39.4°  C.)  with 
sheep's  stomachs  and  calcium  biphosphate  (U.  S.  patent,  1873), 
at  animal  temperature  with  infusion  of  a  pig's  stomach  in  acidu- 
lated water  (Br.  patent,  1869 ;  Bavarian  patent),  with  fresh 
sheep's  stomachs  and  a  very  little  carbonate  of  potash  in  other 
specifications.  By  specifications  at  the  103°  F.  or  at  the  animal 
temperature,  but  practically  at  112°  F.  or  the  necessary  tempe 
rature,  the  digested  tallow  (freed  from  the  cells)  melts,  and  is 
decanted.  It  is  now  allowed  to  cool  to  some  adjusted  tempera- 
ture (86°  to  98°  F.),  and  kept  at  rest  to  "  crystallize  "  out  "  stearin 
in  the  form  of  teats."  The  decanted  liquid  is  further  (or  instead 
of  the  operation  of  "  crystallization  " )  cooled  to  solidify,  and  then 
subjected  to  pressure,  either  in  a  press  or  in  a  centrifugal  ex- 
tractor. The  liquid  product  was  oleomargarin.2 

much  employed,  as  were  also  the  color  tests  of  Chateau.  One  witness  only 
states  the  use  of  Kottstorfer's  method,  and  no  mention,  was  made  of  determina- 
tions by  iodine  numbers,  or  by  the  congealing  and  melting  points  of  the  fatty 
a.cids  after  removal  of  oleic  acid.  Separation  of  oleic  acid  by  action  of  ether  on 
the  lead  salts  was  cited  by  several  of  the  witnesses.  Prof.  Remsen  stated  that, 
in  his  opinion,  "  the  limit's  of  variation  in  the  composition  of  lard  "  had  not  been 
ascertained  so  as  to  enable  a  chemist  to  determine  the  question  of  its  adultera- 
tion. 

1  "Some  Points  in  the  Micro-Chemistry  of  Fats."  JOHN  H.  LONG,  Sc.D. 
Chicago  Academy  of  Sciences,  1885. 

9  Patents  were  issued  in  1871  in  the  United  States  to  H.  Bradley  and  to  W. 
K.  Peyrous  to  make  the  grosser  animal  fats  equal  to  the  best  lard, 'for  cooking 
purposes.  In  1873,  besides  the  U.  S.  issue  of  the  Mege  patent,  a  patent  was  is- 
sued to  E.  Q.  Parafe  for  the  manufacture  of  an  article  designated  as  "  oleo- 
margarin." Further  see  F.  BONDEL.  1874:  "  Extract  from  report  of  MEGE- 


BUTTER.  293 

The  transformation  of  this  into  "  artificial  butter  "  was  under- 
taken bj  Mege  through  churning  with  milk,  or  cows'  udders,  or 
other  treatment.1  In  this  country  manufacturers  of  oleomarga- 
rin  have  been  practically  free  from  any  restrictions  of  patents, 
and  have  conducted  the  details  according  to  methods  governed 
by  the  discretion  of  each  producer.  Indeed,  everywhere  the 
general  essentials  consist  most  often  in  melting  at  60°  to  65°  C. 
(140°  to  149°  F.),  decanting  to  clarify,  "crystallizing"  at  35°  C. 
(95°  F.),  and  pressing  at  this  temperature  for  "prime  margarin" 
or  oleomargarin,  the  solid  residue  being  known  as  "  prime  press- 
tallow,"  and  used  mainly  for  candles. 

At  the  present  time  lard  is  extensively  treated  for  a  product 
corresponding  to  oleomargarin,  and  used  in  butter  substitutes. 
In  these,  also,  cotton-seed  oil,  or  fractions  of  it,  sesame  oil,  and 
cocoanut  oil  have  been  employed  in  some  quarters. 

Oleomargarin  proper,  from  tallow,  has  given  the  following 
numbers :  Sp.  gr.  at  15°  C.,  0.924-0.930  (EAGER)  ;  at  100°  C., 
0.859  (Konigs).  For  percentages  of  stearin  in  oleomargarin, 
corresponding  to  degrees  of  congealing  point  of  the  total  fat 
acids,  see  table  at  p.  272.  Iodine  number,  55.3  (HUBL),  50.0 
(MOORE).  Ilehner's  number  (per  cent,  insoluble  fat  acids),  95.56. 
Saponih'cation  number  of  Kottstorfer,  195  to  197.4.  Reichert's 
number,  0.4  to  0.6  (CORNWALL). 

BUTTER.* — The  immediate  constituents  are  four :  water,  curd 
or  casein,  salt,  and  fats.  Of  these  the  following  percentages 
occur :  Water :  proper  maximum  of  good  butter,  12$  (HEHNER, 
WILEY).  Of  19  samples  reported  by  the  Agricultural  Dept.  the 
lowest  percentage  of  water  was  7.34 ;  the  highest,  14.31  ;  next 
highest,  14.06$.  Of  49  samples  reported  by  the  Board  of  Health 

MOURIEZ  to  the  Board  of  Health  of  the  Department  of  the  Seine  on  the  Product 
named  'Artificial  Butter,'"  Amer  Chemist,  New  York,  4,  370.  MfiGE-Mou- 
RIEZ,  1872:  Moniteur  Scienti,fique,  [3],  2,  No.  369;  Amer.  Chem.,  3,  231.  H. 
A.  MOTT,  1876:  "Manufacture  of  Artificial  Butter,"  Amer.  Chem.,  7,233. 
Agriculture  of  Pennsylvania  Reports,  1885:  pp.  219-265.  "Second  Annual 
Report  of  the 'New  York  State  Dairy  Commissioner,"  1886,  pp.  190,  312. 

1  Further  on  this  subject  see  TIDY  and  WIGNER,  1883:  Analyst,  8,  113. 

2HEiiNER  and  ANGELL,  1877:  "Butter,  its  Analysis  and  Adulterations." 
A.  W.  BLYTH,  1882:  "Foods,"  etc.,  pp.  283-305.  Fox  and  WANKLYN,  1884: 
"Anal,  of  Butter,"  Analyst,  9,  73.  BELL,  method  by sp.  gr.,  1876:  Phar.  Jour.. 
[3],  7,  85.  EASTCOURT,  sp.  gr.,  1876:  Chem.  News,  34,  254.  CASSAMAJOR,  sp. 
gr..  1881:  Jour.  Am..  Chem.  Soc.,  3,  81.  HAGF.R,  odor  test  of  the  burning  fat, 
1880:  Zeitsch.  anal.  Chem.,  19,  238.  WILEY,  1883-85:  Reports  of  Department 
of  Agriculture  at  Washington.  Also,  New  York  State  Dairy  Commissioner's 
Report  for  1886.  See  citations  under  Butter  Fat,  p.  298;  under  the  several 
processes  of  estimation  of  fats,  pp.  256,  257,  260,  269.  SCHEFFER,  1886:  Pharm. 
Rundschau,  4,  248. 


294  FATS  AND   OILS. 

of  Mass.,  1885,  the  maximum  was  12.16  per  cent.  Curd:  from 
0.5  to  1.2$  (WILEY)  ;  averaging  2.2$  (HEHNER  and  ANGELL). 
Salt  :  average,  2.5$  (HEHNER).  Of  22  analyses  of  WILEY,  from 
1.9  to  4.4$.  "Should  never  exceed  8$  "  (H.  and  A.)  Fats: 
the  remainder,  in  the  30  analyses  of  Hehner  and  A.,  highest, 
90.2$ ;  lowest,  76.4$. — A  more  minute  account  of  constituents 
is  undertaken  by  KONIG,'  for  average  of  123  samples :  fat, 
83.27$;  water,  14.49;  casein,  0.71;  milk  sugar,  0.58;  salts, 
0.95  ;  of  the  dry  substance,  the  fat  being  97.34$.  The  fats  con- 
tain traces  of  color  matter,  lecithin,  and  cholesterin,  besides  the 
glycerides. 

Water.  The  estimation  of  the  water  is  accomplished  by  dry- 
ing a  weighed  quantity  of  3  or  4  grams  in  the  air-bath  at  a  tem- 
perature not  above  110°  C.,  using  a  tared  porcelain  or  platinum 
evaporating  dish  of  about  40  c.c.  capacity.  Traces  of  free  vola- 
tile acid  may  be  present,  and  will  be  driven  off.  The  dish  is 
shaken  from  time  to  time.  When  a  nearly  constant  weight  is 
reached  the  difference  of  weight  is  taken.  Absolute  alcohol  may 
be  added  to  favor  the  removal  of  the  last  portions.  Other  opera- 
tors add  a  weighed  quantity  of  pure  dried  sand. 

-Fat.  The  residue  in  the  dish  is  melted,  and  treated  with  por- 
tions of  about  10  c.c.  of  ether  (or  petroleum  benzin),  decanting 
the  clear  ethereal  solution,  filtered  if  necessary,  into  a  weighed 
beaker.  The  filter  should  be  dried  and  weighed  in  a  filter-tube 
or  pair  of  watch-glasses.  The  treatment  is  continued  until  a 
portion  of  the  ethereal  solution,  evaporated  on  a  glass  slide, 
ceases  to  leave  an  oily  residue.  On  evaporation  or  distillation  of 
the  ether  or  benzin  the  weight  of  the  fat  is  obtained,  or  this  may 
be  afterward  calculated  from  the  difference  between  the  weight 
of  the  butter  and  the  sum  of  the  weights  of  the  water  and  the 
curd  with  the  salt.  According  to  WILEY,  the  best  method  of 
separating  the  curd  is  to  dry  the  butter  in  a  dish  (without  sand) 
with  a  small  stirring-rod,  at  105°  C.,  adding  a  little  absolute  alco- 
hol. The  dried  residue  when  cold  (and  after  weighing  for  water- 
loss)  is  treated  with  ether  or  petroleum  benzin,  and  filtered  and 
washed  through  a  Gooch  crucible,  using  an  ether-wash-bottle. 
The  crucible  is  dried  at  105°  C.  The  weight  of  residue,  dimin- 
ished by  the  amount  of  salt  determined  as  sodium  chloride  by 
volumetric  estimation,  equals  the  weight  of  curd. — The  fat  may 
also  be  separated  by  keeping  the  butter  melted  for  some  time  in  a 
tube  until  it  rises  in  a  perfectly  clear  liquid.  In  a  graduated  tube 
the  volume  of  fat  may  be  taken  for  its  approximate  estimation. 

1  "Die  mensch lichen  Nahrungs-  und  Genussmittel,"  1883,  ii.  279. 


BUTTER.  295 

Curd  and  Salt.  The  residue  insoluble  in  ether  is  dried  and 
weighed,  adding  the  increased  weight  of  the  filter  after  drying  it 
with  its  contents  arid  weighing  in  the  filter-tube,  the  sum  repre- 
senting the  curd  plus  the  salt.  The  residue  is  now  burned,  with 
the  filter,  in  the  dish,  to  a  white  ash,  weighed  as  the  salt.  If  for 
any  reason  it  be  desirable,  the  "  salt "  may  be  examined  and  its  so- 
dium chloride  estimated  volumetrically.  Also  the  casein  may  be 
estimated  directly,  with  exclusion  of  milk  sugar,  by  washing  the 
residue  insoluble  in  ether  with  water  acidulated  with  acetic  acid, 
drying,  and  weighing.  Wiley  estimates  the  casein  by  moist 
combustion  with  alkaline  permanganate,  nesslerizing  the  distil- 
late, and  calculating  from  the  nitrogen. 

Separation  of  artificial  coloring  matters  of  butter  fats  and 
oils  (MARTIN,  1885).— To  5  grams  of  the  dry  butter  fat,  or  any 
dry  fat,  add  25  c.c.  of  carbon  disulphide,  and  shake  gently  until 
the  solution  is  complete.  Now  add  25  c.c.  of  water,  made  slightly 
alkaline  with  caustic  soda  or  potash,  and  shake  again  gently.  The 
alkaline  water  will  dissolve  out  the  coloring  matter.  This  can 
be  separated  out  and  determined  qualitatively  by  the  spectro- 
scope or  other  means,  and  quantitatively  by  making  up  a  stand- 
ard solution  of  annato,  or  whatever  the  color  may  be,  and  apply- 
ing the  colorometric  method.  If  the  color  is  slight  a  quantity 
larger  than  5  grams  should  be  taken. — Alcohol  may  be  applied 
to  melted  butter  to  extract  artificial  color.  Besides  annato,  cur- 
cuma and  saffron  are  employed  (MUNICIPAL  LABORATORY  OF  PARIS); 
also  carrot  extract  and  marigold.  Carrot  extract,  in  carbon  disul- 

Ehide  solution,  is  not  dissolved  out  by  alcohol  on  shaking  with  the 
itter,  until  a  drop  of  ferric  chloride  dilute  solution  is  added, 
when,  after  shaking  and  standing,  the  alcohol  extracts  the  carrot 
color  completely,  and  if  no  other  color  be  present  the  carbon  di- 
sulphide solution  becomes  colorless  (R.  W.  MOORE). 

An  account  of  colors  proposed  or  asserted  to  have  been  added 
to  butters  is  given  in  the  report  of  the  N".  Y.  State  Dairy  Com- 
missioner for  1886. 

The  natural  color  of  grass-fed  butter,  to  which  the  name 
"  lactochrome  "  has  been  applied,  is  bleached  by  exposure  to  air 
and  sunlight,  and  disappears  upon  about  eight  hours'  exposure  to 
direct  sunlight  in  a  layer  of  0.5  centimeters  thickness  (SOXHLET). 

Mancidity  of  Sutlers. — KOTTSTORFER  1  estimates  the  free 
acid  of  butters  as  a  measure  of  their  rancidity,  using  the  method 
of  simple  titration  by  alcoholic  potash  in  an  ether  solution  of  the 
fat,  as  adopted  for  fats  in  general  by  GEISSLER,  with  details  given 

1 1879:  Zeitsch.  anal.  Chem.,  18,  436;  Jour.  Chem.  Soc.,  36,  1069. 


296  FATS  AND   OILS. 

on  p.  277.  Three  to  ten  grams  of  clear  butter  fat,  prepared  by 
melting  and  filtering  (as  directed  under  Butter  Fat,  p.  299),  are- 
weighed  into  a  flask  of  about  50  c.c.  capacity,  treated  with  ether 
(freed  from  acidity  as  directed  on  p.  278)  enough  to  dissolve  it, 
phenol-phthalein  added,  the  acid  of  the  mixture  titrated  with  the 
alcoholic  potash,  and  the  value  of  the  latter  taken  by  titration 
with  decinormal  acid,  just  as  directed  on  p.  278.  The  degree  of 
acidity  is  equal  to  the  number  of  c.c.  of  normal  solution  of  alkali 
required  to  neutralize  the  acid  in  100  grams  of  fat.  Also,  c.c. 
normal  solution  X  0.088  =  grams  butyric  acid.  And,  taking  100 
grams  of  fat,  c.c.  normal  solution  X  0.088  =  per  cent,  of  free  fat 
acids,  estimated  as  butyric  acid.  The  percentage  in  the  butter  fat 
X  .85  (or  the  found  proportion  of  fat  in  the  butter)  =  percentage 
of  the  butter. 

The  author  reports  the  acidity  of  the  fats  of  24  butters.  Of 
these  19  did  not  overgo  8  degrees  acidity  of  the  fat,  and  the  average 
acidity  of  the  19  was  4°.  Of  the  five  above  8°  one  reached  41.6°. 
The  author  gives  the  opinion  that  for  good  butter  the  fat  should 
not  exceed  8  degrees  of  acidity  (0.704$  butyric  acid).  The 
average  of  good  butters,  4°  acidity,  corresponds  to  0.372  per 
cent,  of  butyric  acid  in -the  fat,  or  about  0.32  per  cent,  in  the 
entire  butter. 

Detection  of  Foreign  Fats  l>y  their  relation  to  Solvents. — 
Tests  of  butter  fat  by  solvents  have  been  proposed  as  follows : 
HOORN  (1872)  used  petroleum  benzin  of  sp.  gr.  0.69  at  15°  C. 
and  boiling  at  80°-110°C.  FILSINGER  (1880)  applied  a  mixture 
of  4  vols.  ether  of  sp.  gr.  0.725  with  1  vol.  alcohol  of  sp.  gr. 
0.805,  at  18°-19°  C.,  for  12  hours. 

W.  G.  CROOK  (1880)  employs,  as  a  "first  test "  of  butter  fat, 
carbolic  acid  (1  Ib.  Cal vert's  No.  2  with  2  f.  oz.  water).  Of  the 
purified  fat  10  grains  (0.648  gram)  are  treated  in  a  (graduated) 
test  tube  with  30  minims  (1.5  c.c.)  of  the  carbolic  acid,  at  about 
66°  C.  (150°  F.),  with  agitation.  After  some  time  pure  butter 
forms  a  perfect  solution.  Fat  of  tallow  (beef  or  mutton)  or 
lard  separates  in  a  defined  layer,  as  does  olive  oil.  The  percent- 
ages of  volume  of  the  mixture,  taken  by  the  lower  (heavier) 
layer,  are  given  for  each  of  these  fats,  from  44  to  50  per  cent.1 
On  cooling,  more  or  less  precipitate  occurs  in  the  upper  layer. 
So  small  a  proportion  of  lard  as  five  per  cent,  did  not  appear  in 
a  lower  layer,  but  after  24  hours  gave  a  crystalline  turbidity  un- 
like that  of  butter  fat. 

A  method  of  distinction  between  true  butter  fat  and  the  meat 

1  Analyst,  4.  Ill;  Zeitsch.  anal.  Chem.(with  notes  by  LENZ),  19,  369. 


BUTTER.  297 

fats  by  solubility  in  a  mixture  of  atnyl  alcohol  and  ether  is 
proposed  by  E.  ScHEFFER.1  Of  rectified  amyl  alcohol  40  volumes 
are  mixed  with  60  volumes  of  ether  of  sp.  gr.  0.725.  One  gram 
of  the  clear  butter  fat  is  treated,  in  a  test-tube  of  12  c.c.  capacity, 
with  3  c.c.  of  the  solvent  mixture.  After  tightly  corking  the 
tube  is  digested,  with  shaking,  in  a  water- bath  gradually  raised 
from  18°  to  28°  C.  If  the  butter  fat  is  pure  a  clear  solution  is 
obtained.  If  the  solution  be  incomplete  more  of  the  solvent  is 
added  from  a  burette.  For  1  gram  of  unmixed  lard  16  c.c.  of 
solvent  is  required ;  for  1  gram  of  tallow,  50  c.c. ;  for  one  grain 
of  pure  stearin,  550  c.c.  of  the  solvent.  A  mixture  of  10$  lard 
fat  with  butter  fat  took  3.9  c.c. ;  20$  lard  fat,  4.8  c.c. ;  40$  lard 
fat,  6.5  c.c.  ;  90$  lard  fat,  14.4  c.c.  The  theory  of  the  test  is 
simply  that  there  is  more  tristearin  in  meat  fats  than  in  butter 
fat,  although  not  all  the  stearic  aciM  of  the  latter  is  held  in  tri- 
stearin. 

Cohesion  figures 2  are  obtained  in  "  BLYTH'S  Pattern  Pro- 
cess" (1880),  fully  detailed  by  the  author  in  his  work  on 
"  Foods "  (1 882),  giving  distinctions  between  butter  fat  and 
various  other  fats. 

Viscosity  of  Butter  Soaps. — The  recent  report  of  S.  M. 
BABCOCK  3  shows  that  oleomargarin  soaps  are  far  more  viscous 
in  solution  than  butter  soaps.  From  the  differences  given,  in 
tabular  comparison,  it  appears  probable  that  when  this  method 
of  examination  shall  have  been  perfected,  it  will  serve  to  distin- 
guish true  butters  from  mixtures  of  foreign  fats,  even  when  the 
percentage  of  adulteration  is  as  low  as  five.  The  author  states 
that  "  there  is  little  doubt  that  by  making  the  solution  more  al- 
kaline the  addition  of  one  per  cent,  of  adulteration  to  any  given 
sample  of  butter  would  be  shown."  In  the  determinations  the 
New  Viscometer4  of  the  author  was  used.  It  is  of  further  inte- 
rest that  the  insoluble  fat  acids  of  butter  were  found  to  give 
soaps  much  less  viscous  than  those  of  corresponding  mixtures  of 
stearic  and  palmitic  acids  from  meat  fats,  from  which  the  inves- 
tigator was  forced  to  conclude  that  "  it  is  probable  that  the  acids 
of  butter  are  isomers  of  those  from  other  fats." 

Microscopical  Detection  of  Foreign  Fats  in  Butter. — This 

» 1886 :  Pharm.  Rundschau,  4,  248.  Favorable  review  by  H.  W.  WILEY, 
1887:  Science,  9,  114. 

2  TOMLINSON,  1861-62.    CRANE,  1875. 

"Report  of  the  Chemist  to  the  New  York  Agricultural  Experiment  Station, 
Geneva,  N.  Y.,  distributed  Jan.  30,  1887. 

4S.  M.  BABCOCK,  1886:  Chemical  Section  of  Am.  Asso.  Advance.  Sci.,  Buf- 
falo Meeting. 


298  FA  TS  AND  OILS. 

subject  has  been  recently  reported  upon  quite  fully  by  Dr. 
THOMAS  TAYLOR/  Reports  upon  Taylor's  microscopical  method 
have  been  made  by  Prof.  H.  A.  WEBER  a  and  by  Prof.  H.  W. 
WILEY.*  The  last-named  two  observers  do  not  find  that  mix- 
tures of  butter  with  tallow  and  lard  products  can  be  distinguished 
from  pure  butter  by  the  process  of  I)r.  Taylor. 

A  brief  summary  of  microscopical  methods  is  given  under 
"Optical  Methods"  in  the  Report  of  the  N.  Y.  State  Dairy 
Commissioner  for  1886,  p.  271.  A  useful  monograph,  with  cuts 
from  original  micro-photographs,  was  published  by  Dr.  Long  in 
1885,4  recounting  the  examination  of  butter  and  other  fats. 

MYLIUS  (1879B)  has  also  reported  on  the  microscopical  ex- 
amination of  butter. 

An  odor-test  by  the  burning  of  butter  in  a  wick  has  been 
proposed  by  HAGER  (1880).  A  wick  is  placed  in  the  melted 
butter,  lighted  and  burned  for  two  or  three  minutes,  and  extin- 
guished. Oleomargarin  gives  the  odor  of  a  tallow  candle. 
Of  this  test  Messrs.  WALLER  and  MARTIN  (1886)  say  :  "  All  fats 
when  heated  to  decomposition  yield  vapors  of  acrolein  which 
smell  the  same  in  all  cases.  That  part  of  the  fat  volatilized 
which  has  suffered  only  partial  decomposition  is  what  is  observed, 
and  is  at  best  a  very  uncertain  quantity.  Add  to  this  source  of 
error  the  fact  that  old  samples  of  butter  have  naturally  a  decided 
tallowy  taste  and  smell,  and  it  will  be  seen  that  the  odor  in  any 
case  is  a  very  uncertain  test." 

BUTTER   FAT." — Glycerides   of  palmitic   (stearic)    and   oleic 

1  "  Butter  and  Fats.     To  distinguish  one  fat  from  another  by  means  of 
the  Microscope."     By  Thomas  Taylor,  M.D.,  Microscopist  to  the  Department 
of*  Agriculture,   Washington,  D.  C.     Proceedings  of  the  American  Society  of 
Microscopists. — Also  various  papers,  beginning  in  the  Quarfirly  Microscopical 
Journal,  New  York,  1876.     A  paper  in  Proceedings  Am.  Assoc.  Adv.  Sci.,  1885. 

2  Chemist  Ohio  Agricultural  Experiment  Station.     Bulletin  No.  13,  1886, 
March  1. 

3  Chemist  Depart.  Agriculture  at  Washington,  1886. 

4 "Some  Points  on  the  Micro-Chemistry  of  Fats.  JOHN  H.  LONG.  1885. 
Chicago  Academy  of  Sciences." 

*Ber.  d.  chem.  Oes.,  12,  270. 

6 See  citations  under  "  Butter,"  p.  293.  Further,  R.  W.  MOORE,  "Notes 
on  Kottstorfer's  Method,"  etc.,  1884:  Chem.  News,  50,  268;  "Notes  on  the 
Hubl  Method,"  1885  :  Am.  Chem.  Jour.,  6,  416.  On  Reichert's  and  other 
methods.  1885:  Jour.  Am.  Chem.  Soc.,  7,  188;  Analyst,  10,  224.  HANSSEN 
and  SCHMITT,  1884:  Bied.  Cent.,  1884,  707;  Jour.  Chem.  Soc.,  48,  197.  A.  H. 
ALLEN,  "On  Reichert's  Method,"  1885:  Analyst.,  10,  103.  KOTTSTORFER  on 
Reichert's  and  other  methods  compared  with  his  own,  1879:  Zeitsch.  anal. 
Chem.,  iS.435.  REICHARDT,  1884:  Archiv  d.  Phar.,  222,  99;  Zeitsch.  anal. 
Chem.,  23,  565;  Jour.  Chem.  Soc.,  46,  1219. 


BUTTER  FAT.  299 


nds,  and  conjugated  glycerides  of  these  acids  with  volatile  fat 
;ids,  (CnH2nO2),  chiefly  butyric  acid.1 


acids, 
acids, 

Preparation  from  butter,  for  analysis.  The  butter  is  pre- 
served in  the  melted  state,  on  the  water-bath,  with  slight  shaking 
or  stirring  at  intervals,  until  the  fat  rises  in  a  layer  nearly  clear. 
A  dry  "filter  is  prepared  in  a  hot  funnel,  in  a  warm  place,  and  the 
nearly  clear  fat  poured  on  it.  The  filtrate  must  be  perfectly 
clear,  and  not  lose  weight  on  the  water-bath. — For  determination 
of  specific  gravity  the  butter  is  melted  at  50°  to  60°  C.,  in  no 
case  reaching  70°  C.,  and  at  least  50  c.c.  of  filtrate  obtained. 

Specific  ^gravity,  rt,  15°  C.,  0.926  (CASSAMAJOR),  0.9275  (A. 
W.  BLYTH),  0936-0.940  (HAGER)  ;  at  37.8°  C.  (100°  F.)  (water 
at  same=l),  0.911-0.913  (BELL)  ;  at  100°  C.  (water  at  15°  C.=  1), 
0.865-0.868  (KGNiGs) ;  at  100°  C.  (water  at  100°  C.  =  1).  0.901- 
0.904  (WOLKENHAAR)  ;  at  40°  C.  (water  at  same  =  1),  0.912 
(WILEY). 

Melting  Point.  Not  well  defined.  Of  butter,  softens  at 
i>.)..>°  to  31.1°  C.,  and  melts  at  24.4°  to  37.2°  C.  (?ARKES and 
BROWN)  ;  by  the  rising  of  a  light  glass  bulb,  mean  33.7°,  by 
clearing  of  the  liquid,  mean  35.5°  C.  (HASSALL)  ;  by  the  sinking 
of  a  weighted  bulb,  average  of  24  samples,  35.5°  C.  (HEHNER 
and  ANGELL)  ;  by  rising  in  capillary  tubes  immersed  in  water, 
31°  to  36°  C.  (HEISCH)  ;  by  the  running  of  a  solidified  drop  of 
butter,  next  a  thermometer-bulb,  on  a  surface  of  mercury,  27  °  to 
29°  C.  (REDWOOD).  Of  butter  fat,  33°-36°  C.  (WILEY).  Of  the 
fat  acids,  38.0°  C.  (Hum).  Of  msoluble  fat  acids,  39°  to 
43°  C.  (WILEY,  1884). 

Congealing  Point.  Of  biitter  fat,  23°  to  30°  C.  (WILEY). 
Of  the  fat  acids,  35.8°  C.  (Hum,), '37.5°  to  38°  C.  (MUNICIPAL 
LABORATORY  OF  PARIS).  Of  the  insoluble  fat  acids,  34.5°  to 
38°  C.  (WILEY). 

Per  cent,  of  insoluble  fat  acids,  87.5  (HEHNER).  Milligrams 
of  KOH  to  saponify  1  gram  of  fat  (KOTTSTORFER),  227.  Number 
of  c.c.  of  T^  potash  solution  to  neutralize  the  distilled  fat  acids 

1  The  simple  glyceride  tributyrin  does  not  appear  to  be  present  in  butters. 
Conjugated  glycerides,  such  as  C3H5(Ci6H3102)2(C4H702),  are  inferred  to  be  the 
sources  of  the  butyric  acid  of  saponification.  Mr.  HEHNER,  however,  presents 
another  view  :  "Both  the  dipalmitate-monobutyrate  and  the  dioleate-mono- 
butyrate  would  yield  less  insoluble  acids  than  are  found  in  practice,  the  former 
80.2  and  the  latter  84.6  per  cent.  But  a  mixture  of  compound  ethers  such  as 
would  be  obtained  by  substituting  in  the  Irtpalmitate  or  ^rioleate  of  glyceryl  one 
atom  of  the  acid  radical  by  the  radical  of  butyric  acid  would  very  approximately 
yield  such  proportions  of  insoluble  and  soluble  fat  acids  as  are  actually  found." 
It  is  to  be  observed  that  the  question  is  complicated  by  the  presence  of  volatile 
fat  acids  of  larger  molecular  weights  than  butyric  acid.  At  all  events,  the  vola- 
tile fat  acids  obtained  from  100  parts  of  butter  fat  average  about  6  parts. 


300  FATS  AND   OILS. 

from  25  gram  of  fat  (REICHERT),  14.0;  not  less  than  13.0 
(MEISSL).  Iodine  number  of  HUBL,  26.0  to  35.1 ;  fat  from  very 
old  butter,  19.5  (MOORE). 

Butter  Substitutes. — Oleomargarin  is  described  at  p.  292, 
with  some  description  of  treatment  adopted  to  give  it  a  sensible 
resemblance  to  butter.  At  present  prepared  lard  fat  (p.  290)  is 
used  as  much  or  more  than  prepared  tallow  fat.  Frequently  a 
vegetable  oil  is  used  with  either  lard  fat  or  oleomargarin  proper 
(tallow  fat).  The  vegetable  oil  most  used  is  cotton-seed  oil 
(p.  287) ;  after  which  are  to  be  named  sesame  oil  and  cocoanut 
oil.  Of  these  substitutes — two  animal  fats  and  three  vegetable 
fats — only  cocoanut  oil  approaches  in  composition  to  butter  fat. 
It  must  be  remembered  that  the  fats  and  combinations  of  fats- 
presented  as  substitutes  for  butter  are  subject  to  constant  change. 
The  Report  of  the  Dairy  Commissioner  of  the  State  of  New 
York  for  1886  says  "  the  only  materials  used,  according  to  the 
statements  of  the  manufacturers,  are  oleomargarin  ('  oleo-oil  \ 
lard,  cotton-seed  oil,  sesame  oil,  and  annatto."  The  term  "  but- 
terine"  has  been  more  commonly  applied  to  the  mixture  of 
deodorized  lard  and  butter  prepared  by  churning  with  milk. 
"  Suine "  is  a  term  applied  to  a  grade  of  butterine  with  very 
large  proportions  of  lard.  The  work  last  mentioned  describes, 
besides  the  oils  just  named,  those  of  peanut  (ground-nut),  ben, 
mustard,  colza,  rape,  cameline,  cocoanut,  cocoa,  palm,  cacao,  and 
bone. 

Principal  Chemical  Methods  of  Estimation  of  Butter-Fat. 

(1)  Parts  Insoluble  Fat  Acids  in  100  parts  Fat.     Hehner's- 
number,  pp.  250,  256. 

(2)  C.c.  -£j-  alkali  for  Volatile  Fat  Acids  in  2.5  grams  Fat. 
Reichert's  number,  p.  253.     By  Meissl's  method,  p.  253. 

(3)  Milligrams  KOH  to  saponify  1  gram  of  the  Fat.     Kotts- 
torfer's   number,  pp.    254,    257.     PERKINS'S  combination   plan, 
p.  255. 

As  a  single  estimation,  that  denoted  by  Reichert's  number 
(probably  with  Meissl's  manipulation)  is  here  unhesitatingly  re- 
commended in  preference  to  any  other.  But  Hehner's  number 
is  of  nearly  an  equal  value,  and  next  is  ranked  the  number  of 
Kottstorfer,  the  latter  being  of  the  three  the  most  easily  ob- 
tained.— Respecting  (4)  indications  by  specific  gravity,  see  p.  261. 
(5)  Hiibl's  iodine  numbers,  p.  258.  (6)  The  melting  and  congeal- 
ing points  of  butter  substitutes  may  or  may  not  diifer  from  that 
of  true  butter  fat.  Respecting  the  obtaining  and  applying  of 
data  of  melting  and  congealing  points,  "  the  sinking  point,"  and 


BUTTER   FAT.  301 

"  the  point  of  clearance,"  see  p.  265.  (7)  The  percentage  of 
casein,  estimated  by  moist  combustion  for  nitrogen  (WILEY) 
{p.  295),  may  serve  as  an  aid  in  establishing  a  conclusion,  though 
it  is  to  be  remembered  that  a  small  percentage  of  poor  butter 
may  introduce  as  large  a  proportion  of  nitrogen  as  would  be 
found  in  certain  samples  of  the  best  butter. 

Interpretation  of  results. — (1)  Helmets  number. — Hehner 
gives  as  extremes  for  true  butter  fats  86.6  and  88.5  per  cent,  of 
insoluble  fat  acids.  If  "lower  than  88  per  cent.,  the  butter 
must  be  declared  genuine"  ;  if  "higher  than  88.5  per  cent.,  we 
conclude  that  adulteration  has  taken  place  " ;  while,  "  in  case 
sophistication  is  proved  beyond  a  doubt,  we  base  the  calculation 
upon  a  lower  figure,  namely,  87.5."  Taking,  then,  87.5  as  the 
percentage  of  insoluble  fat  acids  in  true  butter,  and  taking  95.5 
as  the  percentage  of  the  same  in  fats  used  as  adulterants  (p.  256), 
we  have  8  as  the  difference  of  Hehner's  number  due  to  the  sub- 
stitution of  foreign  fat  for  butter.  If  now 

a  =  parts  of  insoluble  fat  acids ]  In  100  parts 

A  =       u         foreign  fat I         ,    ,£  , 

B=       "         butter  fat t  the  tat 

C  =       "         entire  butter  equal  to  the  butter  fat  J 
D  =       "         true  butter  in  100  parts  of  the  entire  butter  ana- 
lyzed, 

8  :  ^—87.5::  100  :  A.      Or,  A  =  12.5  (0  —  87.5). 

B  =  100  —  A. 
851  :  100 ::B  :  C.      Or,  C  =  1.1765 B. 

A  +  C:  100::C:  D.      Or,  D  =  ^r§.. 

.A.  — j—  vv 

Of  course  the  factors  87.5,  95.5,  and  85  are  subject  to  chemical 
estimations  of  the  per  cent,  of  insoluble  fat  acids  in  butter  fat 
and  in  adulterating  fats,  and  the  per  cent,  of  butter  fat  in  true 
butter.  The  per  cent,  of  insoluble  fat  acids  is  itself  the  best 
statement  of  results  by  Hehner's  method,  and  it  should  be  given, 
for  information  of  those  who  can  understand  it,  while  the  calcu- 
lated per  cent,  of  true  butter  is  given  only  when  required,  and 
may  be  accompanied  with  a  statement  of  the  conditions  on  which 
it  is  based.  The  conversion  of  the  percentage  of  butter  fat  into 
that  of  entire  butter  is  more  properly  made  by  use  of  the  actual 
percentage  of  total  fat  found  in  the  butter  as  sold,  instead  of  the 
general  average  figure,  85,  above  assumed.  But  even  with  the 
use  of  this  factor  from  the  butter  in  question,  there  remains  the 

'Seep.  294. 


302  FA  TS  AND  OILS. 

uncertainty  as  to  how  much  of  the  water  in  the  sample  was  in- 
troduced as  a  part  of  the  true-butter  fraction,  and  how  much  was 
introduced  as  a  part  of  the  oleomargarin  fraction,  or  was  due  to 
manipulation  of  the  mixture.  Therefore  the  opinion  is  here 
given  that  the  simple  figure  known  as  Hehner's  number  is  the 
best  expression  of  results  by  Hehner's  method  (See  the  follow- 
ing corresponding  discussion  of  interpretation  of  Kottstorfer's 
number,  p.  304).  A  table  of  Hehner's  numbers  of  the  principal 
fats  concerned  in  butter  adulteration  is  given  on  p.  256.  Of  29 
true  butters  reported  upon  by  the  Department  of  Agriculture  at 
Washington,1  live  gave  between  88.5  and  89.0  per  cent,  of  inso- 
luble fat  acids,  three  Alderneys  gave  from  89.0  to  89.26  per  cent., 
and  one,  an  Alderney,  gave  89.89  per  cent.  The  Food  Analyst 
of  the  Pennsylvania  Board  of  Agriculture,  Prof.  C.  B.  Cochran, 
found  the  extremes  of  fixed  fat  acids  from  fat  of  25  genuine  but- 
ters to  be  86.T  to  87.7  per  cent.2 

Rancid  Butters  give  nearly  the  same  percentages  as  fresh 
butters  (FLEISCHMANN  and  YIETH),  the  slight  differences  being 
in  the  direction  of  an  increase. 

(2)  Interpretation  of  results  by  ReicJierfs  Estimation.* — The 
c.c.  of  decinormal  alkali  to  neutralize  the  volatile  acids  of  2.5 
grams  of  fat.  Each  c.c.  decinormal  alkali  indicates  0.0088  gram 
of  butyric  acid;  and  0.0088  gram  butyric  acid  in  2.5  grams  of 
fat  is  equal  to  0.00352  gram  butyric  acid  in  1  gram  of  fat,  or 
0.352  in  100  grams  of  fat.  Then,  Reichert's  number  X  0.352 
=  per  cent,  of  volatile  acids  (as  butyric  acid)  in  the  fat ;  and  per 
cent,  butyric  acid  -^-  0.352  =  Reichert's  number. 

Reichert  found  true  butters  to  give  numbers  from  13.55  to 
14.45,  average  14.0,  and  declared  any  butter  giving  less  than 
12.0  c.c.  must  be  adulterated.  Dr.  G.  C.  CALDWELL  reported  to 
New  York  State  Board  of  Health  estimations  of  27  samples  of 
butter  yielding  Reichert's  numbers  from  12.  7  to  15.5.  Messrs. 
WALLER  and  MARTIN  (Report  New  York  State  Dairy  Commis- 
sioner, 1886)  obtain,  from  26  American  butters,  on  first  50  c.c.  of 
distillate,  numbers  of  Reichert's  method  from  12.2  to  16.3  as  ex- 
tremes. They  also  carried  eight  additional  distillates,  in  exten- 
sion of  Meissl's  plan,  by  which  they  compute  that  only  from  75 
to  85  per  cent,  of  the  total  volatile  acid  comes  over  in  the  first 
50  c.c. 

Prof.  C.  B.  Cochran,  West  Chester,  Pa.,  Food  Inspector  of 


1 1884:  p.  63,  Report  of  the  Chemist,  H.  W.  WILEY. 

2  Unpublished  report  communicated  to  the  author. 

3  Directions  for  estimation  and  bibliography,  p.  253. 


BUTTER  FAT. 


303 


the  Pennsylvania  Board  of  Agriculture,1  has  found  the  extreme 
minimum  of  the  Reichert's  numbers  of  known  genuine  butters  to 
be  12.5  (c.c.  of  tenth-normal  sol.  for  2|  grams  fat) ;  and  this  che- 
mist holds  that  Reichert's  number  11.5  is  the  proper  minimum 
limit  to  govern  an  analyst  in  condemning  butters  inspected  by 
law.  He  has  finally  come  to  rely  almost  exclusively  upon  the 
Reichert's  numbers. 

In  Reichert's  own  analyses  lard  gave  0.30 ;  raw  tallow,  0.25  ; 
rape  oil,  0. 25 ;  oleomargarin  butter,  0.95.  Cocoanut  oil  gave 
3.70. 

Reichert  proposes  this  formula  for  calculation  of  per  cent. 
of  true  butter  fat  in  an  admixture  of  fats  :  (Reichert's  number 
—  0.30)  X  7.30  =  percentage  of  true  butter  fat.  The  probable 
error  =  ±  0.24  X  (Reichert's  number —  0.30). 

MEISSL,  using  his  modification  (p.  253),  places  the  minimum 
limit  of  the  Reichert  number  at  13.  R.  W.  MOORE  (1885 3)  re- 
ports the  following  tabulated  comparisons  of  chemical  data  for 
the  distinction  of  butter  from  its  substitutes,  with  discussion  of 
the  various  methods,  and  recommends  Reichert's  method,  espe- 
cially when  cocoanut  oil  is  in  question.  JELubl's  number  gives  the 
percentage  of  iodine  taken  (p.  258) : 


._.•..-;  ' 

Numbers  of 

HEHNEB. 

KOTTSTOR- 
FER. 

HUBL. 

REICHERT. 

Butter,  samples  

j  86.01 
\  86.49 
(  95.56 

1  89.50 

227.0 
224.0 
197.4 
195.0 

227.5 

19.5 

38.0 
50.0 
50.0 

35.4 

13.25 
13.1. 
0.6 
0.4 

8.7 

Oleomargarin,  samples.  .  . 
Butter,  50$  .  . 

Oleomargarin,  27.5$. 

Cocoanut  oil,  22.5$. 

The  specific  gravity  of  the  cocoanut  oil  used  was  0.9167  at  37.7° 
C.,  "  which  is  sufficiently  high  to  bring  the  mixtures  above  the 
sp.  gr.  of  0.911,  which  is  that  of  butter."  WALLER  and  MARTIN 
(1886)  found  cocoanut  oil  to  give  a  Reichert's  number  of  from 
2.7  to  3.7. 


1  Unpublished  communication  to  the  author. 

2  Jour.  Am.  Chem.  Soc.,  7,  188;  Analyst,  10,  224. 


304  FA  TS  AND  OILS. 

MEISSL  (1879)  found  that  soft  butters  yield  higher  propor- 
tions of  volatile  acids  than  hard  butters.  Butter  oil  gives  higher 
numbers  in  Reichert's  method  than  entire  butter. 

Rancidity  reduces  the  quantity  of  the  volatile  acids  of  butter. 

The  quantity  of  volatile  fat  acids  by  Reicherfs  method  is  by 
no  means  identical  with  the  quantity  of  soluble  fat  acids,  though 
the  latter  should  include  the  former.  It  will  be  observed  that 
insoluble  fat  acids  are  filtered  out  of  the  distillate,  if  obtained  in 
it,  in  Reichert's  operation.  A  good  number  of  the  analysts  of 
butter  practise  the  estimation  of  its  soluble  fat  acids  by  titration 
of  the  filtrate  and  washings  from  the  insoluble  fat  acids.  With- 
out doubt  these  results  have  value.  Along  with  Hehner's 
method  they  are  easily  obtained  in  a  combination  process.  Di- 
viding per  cent,  butyric  acid  by  0.352,  the  quotient  may  be  com- 
pared with  Reichert's  number.  It  is  believed,  however,  that 
Reichert's  estimation  of  volatile  acida  has  greater  constancy  than 
an  estimatio'n  of  the  soluble  fat  acids,  and  therefore  the  combi- 
nation plan  of  PERKINS  (p.  255)  is  given  in  this  work  instead  of 
processes  including  estimation  of  soluble  acids,  without  distil- 
lation. 

The  per  cent,  of  soluble  fat  acids  in  butter  averages  at  least 
5.5,  and,  according  to  most  authorities,  should  not  fall  below  5. 
Messrs.  WAIXER  and  MAKTIN  (1886)  obtained  from  26  American 
butters  (genuine)  the  extremes  of  from  4.49  to  7.25$  volatile 
acids,  as  butyric  acid,  six  or  seven  washings  with  hot  water  being 
taken  for  the  total  filtrate  titrated  (p.  251).  It  may  be  remarked 
that  the  percentage  of  total  volatile  fat  acids,  from  the  same  but- 
ters, show  less  variation,  the  extremes  standing  5.52  and  6.87, 
as  butyric  acid,  these  being  obtained  by  prolonged  distillation 
(beyond  the  50  c.c.  distillate  of  Reiehert). 

(3)  Interpretation  of  Kottstorfer 's  number,  the  milligrams 
of  KOH  neutralized  in  saponifying  1  gram  of  fat :  a  measure  of 
the  saturating  power  of  the  total  fat  acids.  Directions  for  the 
estimation,  p.  254 ;  Table  of  numbers  for  Fats  and  Oils,  p.  257. 


Bibliography,  pp.  254,  298. 
In  Kottstorfer's 


's  conclusion  (1879)  a  number  not  lower  than 
221.5  indicates  unadulterated  butter,  this  being  the  lowest  limit 
of  true  butter.  The  highest  limit  he  placed  at  233,  and  the  ave- 
rage 227.  For  oleomargarin  the  number  195.5  was  taken  as  the 
average,  and  for  lard  the  same.  If  a  number  (71)  be  lower  than 
221  5,  the  percentage  of  oleomargarin  (x)  is  found  by  the  for- 
mula, x  =  (227  —  n)  3.17. 

That  is,  if  the  limit  number  be  overpassed  by  any  butter  in 
question,  its  amount  of  adulteration  is  judged  by  comparison 


BUTTER  FAT.  305 

with  the  average  number  of  true  butter  —  a  plan  corresponding  to 
that  followed  under  Hehner's  method.  Then  we  have  as  data 
for  calculating  the  percentage  (x)  of  adulterating  fat,  from  Kotts- 
torfer's  number  (n)  for  any  mixture  of  fats  : 

227  —  195.5  =  31.5)  :  (227  —  n)::  100  :  x 
And 


The  average  number  of  any  adulterating  fat  in  question  is 
to  be  substituted  for  195.5  ;  and  the  number  227  is  to  be  held 
subject  to  correction  as  the  average  number  for  true  butter.  The 
difference  31.5  may  be  varied  by  ±  5.75  in  cases  of  extreme 
composition  of  true  butter  fat,  causing  ±18$  difference  in  the 
interpretation. 

Rancid  butters  gave  Kottstorfer  a  number,  for  the  fat,  1.5 
lower  than  fresh  butter. 

Mr.  WIGNEB,  in  1879,  stated  that  "any  butter  fat  which  re- 
quires near  22.6$  KOH  for  saponih'cation  [number  226],  as  de- 
termined by  the  titration  process,  may  be  safely  passed  as  gen- 
uine ;  but  any  lower  result  should  be  checked  by  a  further 
analysis:" 

(4)  Specific  Gravity  as  a  means  of  distinguishing  the  Fat 
of  Butter  from  that  of  its  Substitutes.1  —  Specific-gravity  list, 
p.  299.—  Taken  by  Mr.  Bell  as  a  liquid  at  100°  F.  (water  at  same 
=  1),  using  a  specific-gravity  bottle.  By  Mr.  Cassamajor,  as  a 
solid,  at  15°  C.,  floated  in  alcohol  of  known  density.  By  Mr. 
"Wigner,  as  a  liquid,  at  temperatures  adjusted  (water  at  60°  F. 
=  1)  by  the  suspension  of  specific-gravity  bulbs,  using  data 
furnished.  By  Mr.  Estcourt,  as  a  liquid,  at  near  the  boiling 
point  of  water,  by  use  of  the  Westphal  balance. 

According  to  Mr.  Bell,  butter  fat  (not  rancid)  rarely  falls  be- 
low 0.910  (at  100°  F.,  water  at  same),  the  usual  range  being  0.911 
-0.913,  and  the  fat  of  rancid  butter  sometimes  falling  in  density 
to  0.908.  The  fats  of  tallow  and  lard,  0.902.8  to  0.904.6. 

Cassamajor  found  that  true  butter  fat,  congealing  in  the  al- 
cohol from  melted  drops,  was  held  in  equilibrium  at  15°  C.  by 
alcohol  of  specific  gravity  0.926  [15.6°  C.]  or  53.7  per  cent. 
[volume].  Oleomargarin,  treated  in  the  same  way,  was  held  in 
equilibrium  at  15°  C.  by  alcohol  of  sp.  gr  0.915,  or  of  59.2  per 

1  J.  BELL,  1876:  Phar.  Jour.  Trans.,  [3],  7,  85.  WIGNER,  1876:  Analyst, 
i,  145.  CASSAMAJOR,  1881:  Jour.  Am.  Chem.  Soc.,  3,  83;  Chem.  News,  44,  309; 
Jour.  Chem.  Soc.,  42,  341.  HEHNER  and  ANQELL,  1877:  "Butter,"  pp.  76-86. 
BENEDIKT,  1886:  <  '  Analyse  der  Fette,"  p.  263. 


306  FATS  AND  OILS. 

cent,  strength  [by  vol.]  Quoting,  also,  the  experiments  of 
LETTNE  and  HARBURET,'  Mr.  Cassamajor  proposed  to  estimate 
proportions  of  oleomargarin,  in  mixture  with  butter  fat,  by  a 
scale  of  graded  strengths  of  alcohol  between  53.7$  and  59.2,  cal- 
culatingon  the  basis  of  5.5  alcoholic  percentage  for  total  differ- 
ence between  the  two  fatty  bodies 

Cocoanut  oil  has  sp.gr.  0.916T  at  37.7°  C.  (100°  F.),  about 
0.0037  above  the  highest  density  of  butter  fat,  so  that  mixtures 
of  oleomargarin  and  cocoanut  oil  could  easily  give  the  specific 
gravity  of  butter  fat.  Rancid  butter  fat  approaches  in  specific 
gravity  to  the  oleomargarin  fats.2 

Specific  Gravities  of  Fats  and  Oils  are  given  in  Tables 
pp.  262,  265. 

C.  B.  CocHRAN3  has  used  a  glass  bulb  displacing  1  c.c.  and  of 
sp.  gr.  3.4,  for  the   "  sinking  point "  temperature,  and  has  com- 
pared the  data  so  obtained   with  figures  of  sp.  gr.  at  100°  F. 
(water  at  same  —  1),  with  results,  for  spurious  butters,  as  follows : 
Specific  gravity,  905.97  to  911.89. 
Sinking  point,  92.5°  F.  to  99°  F. 

The  Iodine  Numbers  of  HUBL,  of  frequent  application  in 
the  analysis  of  Fats  in  general,  have  a  very  limited  application 
in  the  analysis  of  butter,  so  far  as  shown  for  any  adulterations 
hitherto  made.  Directions  for  the  estimation,  p.  258 ;  tables, 
p.  259. 

Scope  of  Chemical  Analyses  of  Butter  and  forms  of  Certifi- 
cates, as  required  of  Public  Analysts.* 

The  following  form  of  report  is  used  (in  1886)  as  a  tag- 
record  by  the  Inspector  of  Foods  of  the  city  of  Boston.  Mass., 
under  the  regulations  of  the  city  and  the  laws  of  the  State : 

"  BUTTER  :  Date, ;  Time, A.M.  -    -  P.M.     If  a  store : 

Proprietor's  name, ;  No.  —  ;  Street, ;  sold  by ; 

price  paid, ;  quantity, Ib. ;  wholesalers  name, ; 

jjrice  paid  ditto, ;  District. .  If  a  wagon :  Proprie- 
tor's name,  ;  name  on  wagon, ;  driver  in  charge, 

;     locality,    .      Butter, .       Oleomargarin, . 

1 1881:  Municipal  Laboratory  of  Paris:  Moniteur  Scientifique. 
3  Further  on  the  effects  of  Rancidity,  JONES,  1879:  Analyst,  4,  39. 

3  Food  Inspector,  Penn.  Board  of  Agriculture,  in  unpublished  communica- 
tion made  (1886)  to  the  author. 

4  DEPARTMENT  OF  AGRICULTURE  AT  WASHINGTON,  Reports  for  1884,  p.  55. 
Mass.   State  Board  of  Health,   etc.,   Reports  for  1884,   pp.  97,  118;    1885, 
p.  132. 


BUTTER.  307 


.DULUJimtJ,    -      . 

Jlllltai/lUll       UUbl/Cl,     -              .               »Y  HCL11C1       UJiUJVCU 

piopcrlj,          . 
Analysis  .No.  — 
F-it 

Cui'fls     -  •  ••            A  sli 

W-itor 

Tricril  nl  \\t±     \nif\a 

JJ 

The  report  of  tlie  State  Board  of  Health,  etc. ,  of  the  State  of 
Massachusetts  for  1885  gives  a  list  of  samples  of  butter  reported 
upon,  with  items :  "  Inspector's  number,  price  per  pound,  per 
cent,  insoluble  fatty  acids,  remarks."  "  The  highest  limit  of  in- 
soluble fatty  acids  in  genuine  butter  fat — 90  per  cent. — has  been 
taken  as  the  dividing  line  between  the  genuine  and  the  artificial 
product."  l 

1  The  Laws  of  Massachusetts  in  relation  to  the  Sale  and  Inspection  of  Hutler, 
Oleomargarin,  Cheese,  etc. 

[Sections  17,  18,  19,  20,  and  21  of  Chap.  56  of  the  Public  Statutes,  as  amended 
by  Chap.  310  of  the  Acts  of  1884,  and  Chap.  352,  Acts  of  1885  ] 

SECTION  1 7.  Whoever,  by  himself  or  his  agents,  sells,  exposes  for  sale,  or 
has  in  his  possession  with  intent  to  sell,  any  article,  substance,  or  compound 
made  in  imitation  or  semblance  of  butter  or  as  a  substitute  for  butter,  and  not 
made  exclusively  and  wholly  of  milk  or  cream,  or  containing  any  fats,  oils,  or 
grease  not  produced  from  milk  or  cream,  shall  have  the  words  il  Imitation  But- 
ter," or,  if  such  substitute  is  the  compound  known  as  "  Oleomargarin,"  then  the 
word  "  Oleomargarin,"  or,  if  it  is  known  as  "  Butterine,"  then  the  word  "  But- 
terine."  stamped,  labelled,  or  marked,  in  printed  letters  of  plain,  uncondensed 
Gothic  type  not  less  than  one-half  inch  in  length,  so  that  said  words  cannot  be 
easily  defaced,  upon  the  top  and  side  of  every  tub,  firkin,  box,  or  package  con- 
taining any  of  said  article,  substance,  or  compound.  And  in  cases  of  retail  sales 
of  any  of  said  article,  substance,  or  compound  not  in  the  original  packages,  the 
seller  shall,  by  himself  or  his  agents,  attach  to  each  package  so  sold,  and  shall 
deliver  therewith  to  the  purchaser,  a  label  or  wrapper  bearing  in  a  conspicuous 
place  upon  the  outside  of  the  package  the  words  "Imitation  Butter,"  "Oleo- 
margarin," or  "  Butterine,"  as  the  article  may  be,  in  printed  letters  of  plain,  un- 
condensed Gothic  type  not  less  than  one-half  inch  in  length. 

SEC.  18.  Whoever,  by  himself  or  his  agents,  sells,  exposes  for  sale,  or  has  in 
his  possession  with  intent  to  sell,  any  article,  substance,  or  compound  made  in 
imitation  or  semblance  of  cheese  or  as  a  substitute  for  cheese,  and  not  made  ex- 
clusively and  wholly  of  milk  or  cream,  or  containing  any  fats,  oils,  or  grease 
not  produced  from  milk  or  cream,  shall  have  the  words  "  Imitation  Cheese  " 
stamped,  labelled,  or  marked,  in  printed  letters  of  plain,  uncondensed  Gothic 
type  not  less  than  one  inch  in  length,  so  that  said  words  cannot  be  easily  de- 
faced, upon  the  side  of  every  cheese-cloth  or  band  around  the  same,  and  upon 
the  top  and  side  of  every  tub,  firkin,  box,  or  package  containing  any  of  said  ar- 
ticle, substance,  or  compound.  And  in  cases  of  retail  sales  of  any  of  said  arti- 
cle, substance,  or  compound  not  in  the  original  packages,  the  seller  shall,  by 
himself  or  his  agents,  attach  to  each  package  so  sold,  and  shall  deliver  there- 
with to  the  purchaser,  a  label  or  wrapper  bearing  in  a  conspicuous  place  upon 
the  outside  of  the  package  the  words  "Imitation  Cheese,"  in  printed  letters  of 
plain,  uncondensed  Gothic  type  not  less  than  one  inch  in  length. 

SEC.  19.  Whoever  sells,  exposes  for  sale,  or  has  in  his  possession  with  in- 


3o8  FA  TS  AND  OILS. 

Under  the  action  of  the  Dairy  Commissioner  of  New  York 
State  some  of  the  analysts  of  butter  (in  1886)  report  upon  print- 
ed blanks  as  follows  for  butters  found  to  be  spurious :  "  Certifi- 
cate of  Analysis  of  a  -  —  sample  of.-  -  'Butter';  marked 

— ;  received  iroin  -  — ,  per  -  — ,  on  -  — .  This  sample 

contains :  Animal  [vegetable]  and  Butter  Tor  total]  Fat, ; 

Curd,-  -;  Salt  (ash),  -  -;  Water  at  100°  C.} .  Analy- 
sis of  the  Fat  present  in  the  sample :  Soluble  fatty  acids  (by 

distillation)  (on  a  dry  basis),  —  — ;  Insoluble  fatty  acids, ; 

Specific  Gravity  of  the  dry  fat,  at  100°  F.  Titer,  -  -  [Kei- 
chert's  number].  (This  sample  is  composed  -  -  of  foreign  fat, 
and  is  not  produced  from  unadulterated  milk,  or  cream  from  the 
same.  It  contains  coloring  matter,  whereby  it  is  made  to  re- 
semble butter,  the  product  of  the  dairy,  and  is  made  in  imitation 
and  semblance  of  butter  produced  from  unadulterated  milk,  or 
cream  from  the  same.)  " 

The  Food  Analyst  of  the  Board  of  Agriculture  of  Penn.^ 
Prof.  COCHRAN,  cites  the  following  results  of  official  analyses  of 
butters : 


tent  to  sell,  any  article,  substance,  or  compound  made  in  imitation  or  semblance 
•of  butter  or  cheese,  or  as  a  substitute  for  butter  or  cheese,  except  as  provided  in 
the  two  preceding  sections,  and  whoever  defaces,  erases,  cancels,  or  removes 
any  mark,  stamp,  brand,  label,  or  wrapper  provided  for  in  said  sections,  or 
changes  the  contents  of  or  in  any  manner  shall  falsely  label,  stamp,  or  mark 
any  box,  tub,  article,  or  package  marked,  stamped,  or  labelled  as  aforesaid, 
with  intent  to  deceive  as  to  the  contents  of  said  box,  tub,  article,  or  pack- 
age, shall  for  every  such  offence  forfeit  to  the  city  or  town  where  the  offence 
was  committed  one  hundred  dollars,  and  for  a  second  and  each  subsequent  of- 
fence two  hundred  dollars. 

SEC.  20.  Inspectors  of  milk  shall  institute  complaints  for  violations  of  the 
provisions  of  the  three  preceding  sections  when  they  have  reasonable  cause  to 
believe  that  such  provisions  have  been  violated,  and  on  the  information  of  any 
person  who  lays  before  them  satisfactory  evidence  by  which  to  sustain  such 
complaint.  Said  inspectors  may  enter  all  places  where  butter  or  cheese  is 
stored  or  kept  for  sale,  and  said  inspectors  shall  also  take  specimens  of  sus- 
pected butter  or  cheese  and  cause  them  to  be  analyzed  or  otherwise  satisfactori- 
ly tested,  the  result  of  which  analysis  or  test  they  shall  record  and  preserve  as 
evidence;  and  a  certificate  of  such  result,  sworn  to  by  the  analyzer,  shall  be  ad- 
mitted in  evidence  in  all  prosecutions  under  this  and  three  preceding  sections. 
The  expense  of  such  analysis  or  test,  not  exceeding  twenty  dollars  in  any  one 
case,  may  be  included  in  the  costs  of  such  prosecutions.  Whoever  hinders,  ob- 
structs, or  in  any  way  interferes  with  any  inspector,  or  any  agent  of  an  inspec- 
tor, in  the  performance  of  his  duty,  shall  be  punished  by  a  fine  of  fifty  dollars 
for  the  first  offence,  and  of  one  hundred  dollars  for  each  subsequent  offence. 

SEC.  21.  For  the  purposes  of  the  four  preceding  sections,  the  terms  "but- 
ter" and  4<  cheese"  shall  mean  the  products  which  are  usually  known  by  these 
names,  and  are  manufactured  exclusively  from  milk  or  cream,  with  salt  and 
rennet,  and  with  or  without  coloring  matter. 


BUTTER. 


309 


JKeichert's   num- 
ber. 

Hehner's  num- 
ber. 

'Butter"    reported 
to  be 

No.    1  

3.1  c.c. 

88.9^ 

Not  genuine. 

2  

4.2 

93.45 

«            a 

3  

3.0 

92.9 

u            a 

4 

14.0 

Genuine. 

5.               .     . 

12.6 

a 

6.             

1.6 

Not  genuine. 

7  

14.15 

Genuine. 

8  

13.0 

u 

9  

14.15 

tt 

10  

1.5 

Not  genuine. 

11  

0.75 

a            u 

12  

1.0 

tt            a 

13  

11.7 

Passed. 

14  

0.7 

Not  genuine. 

15. 

0.85 

u            u 

16. 

1.6 

u            u 

IT. 

1.0 

a            u 

18.     . 

2.4 

«            a 

19. 

12.1 

Passed. 

20..    . 

5.2 

Not  genuine. 

21  

12.8 

Passed. 

22  

0.6 

Not  genuine. 

23  

13.7 

Genuine. 

24.  .  ,  

3.0 

Not  genuine. 

25  

12.5 

Passed. 

26  

12.2 

u 

27  

16.3 

u 

281  

13.3 

u 

29. 

15.2 

it 

30.. 

15.5 

u 

The  Agricultural  Department  at  Washington  for  1884,  Prof. 
WILEY,  Chemist,  reports  tabulated  analyses,  with  statements  of 
u  No.,  name,  made  at,  made  by,  bought  at,  price,  color  [to  the 
eye],  water,  casein,  salt,  fat,  melting  point,  solidifying  point, 
saturation  equivalent  (56000  -f-  Kottstorfer's  number),  soluble 

'•No.  28:  Fats,  78  per  cent. ;  water,  17.38  per  cent.;  curd,  2.4  per  cent.  ; 
ash,  2.21  per  cent. 


310  FATS  AND  OILS. 

acid  (in  per  cent,  as  butyric,  obtained  bj  titration  of  filtrate 
from  insoluble  fat  acids),  insoluble  acid,  melting  point  insoluble 
acid,  solidifying  point  insoluble  acid,  saturation  equivalent  of 
insoluble  acid  "  (56000  -f-  Kottstorfer's  number  for  the  insoluble 
acids). 

What  is  a  sufficient  chemical  analysis  of  butter  f — A  single 
faithful  estimation,  whether  of  (1)  the  insoluble  fat  acids,  (2)  the 
soluble  acids  distilled,  or  (3)  the  saponification  number,  as  these 
estimations  are  detailed  in  pp.  250  to  255,  may  give  such  a  result 
that  no  further  evidence  is  needed  to  prove  the  butter  to  be  not 
a  genuine  one.  And  the  result  of  an  estimation  by  any  one  of 
these  established  methods  may  be  in  itself  sufficient  to  prove 
that  a  certain  sample  does  not  consist  mainly  or  largely  of  oleo- 
margarin.  Besides,  oleomargarin,  lard  products,  and  cotton-seed 
oil,  or  any  mixture  of  these  three,  may  be  distinguished  with 
certainty  from  pure  butter  fat  by  any  one  of  the  methods  just 
named  (Hehner's,  Reichert's,  or  Kottstorfer's).  Further,  any 
mixture  of  oleomargarin,  or  lard  product,  or  cotton-seed  oil,  or 
combination  of  these  foreign  fats,  with  a  smaller  proportion  of 
butter  fat  of  average  or  nearly  average  composition,  must  be 
clearly  revealed  not  a  pure  butter  fat  by  the  result  of  a  true  esti- 
mation according  to  Hehner,  or  Reichert,  or  Kottstorfer.  Adul- 
teration with  the  foreign  fats  above  named,  when  in  proportions 
not  less  than  half,  and  when  with  butter  fat  of  about  average 
composition,  can  invariably  be  declared  as  adulterations  by  analy- 
sis under  one  of  the  three  methods  here  referred  to.  And  what 
is  here  stated  as  true  of  oleomargarin  or  prepared  tallow  fat,  and 
lard  fat,  and  the  fat  of  cotton-seed  oil  is  known  to  be  true  of 
numerous  vegetable  fats,  some  of  which  have  been  used  in  butter 
substitutes,  and  is  true  of  known  fats  with  a  very  few  excep- 
tions. 

When  a  question  of  small  proportions  of  foreign  fats  in  mix- 
ture with  large  proportions  of  average  butter  fat  is  presented,  it 
is  to  be  understood  that  there  is  a  limit  to  the  diminution  which 
foreign  fat  may  undergo  and  still  remain  capable  of  detection  by 
one  of  the  estimations  above  enumerated,  or  by  any  mode  of 
analysis.  Just  what  percentage  of  foreign  fat  marks  such  limit 
it  is  difficult  to  state.  Granting  that  the  butter  fat  of  the  mix- 
ture be  of  average  composition,  the  limit  must  lie  in  such  low 
percentages  of  foreign  fat  as  would  be  of  improbable  occurrence 
in  adulteration  for  commercial  ends.  But  when  the  possibil- 
ity of  admixture  with  butter  fat  of  exceptional  composition  is 


BUTTER.  311 

introduced  into  the  question,  the  limit  of  quantity  of  foreign  fat 
capable  of  detection  by  chemical  estimation  rises  to  a  place  among 
percentages  which  are  quite  possible  among  the  devices  of  adul- 
teration. If  the  article  be  rancid  a  somewhat  abnormal  compo- 
sition of  butter  fat  may  have  been  acquired. 

A  rule  has  prevailed,  in  the  interpretation  of  results  under 
several  methods  of  analysis,  that  only  when  the  result  stands  out- 
side of  the  extremes  obtained  among  the  results  of  varying  sam- 
ples of  genuine  butter  fat  shall  a  butter  be  declared  (qualitative- 
ly) adulterated.  But  when  so  declared  adulterated  a  (quantitative) 
statement  of  the  proportion  of  the  adulteration  may  be  based 
upon  the  deviation  from  the  average  of  results  of  genuine  butter 
fat.  This  rule  has  been  discussed  at  p.  302.  Its  bearing  may 
be  illustrated  by  an  application  under  Helmer's  method,  as  fol- 
lows :  If  the  insoluble  fat  acids  be  found  at  88.0$  of  the  clear  fat 
the  article  is  declared  not  adulterated.  If  found  at  88.5$  the  ar- 
ticle is  not  declared  adulterated  (on  this  evidence  alone).  If 
found  at  88.6$  insoluble  fat  acids,  an  adulteration  of  13f$  of 
foreign  fat  in  the  total  fat  is  reported  under  the  rule.  At  the 
same  time,  if  the  extreme  limit  of  88.5$  insoluble  acids  in 
exceptional  butter  fat  be  taken  as  the  datum  of  calculation 
for  the  quantitative  report  on  88.6$,  as  was  taken  for  the  quali- 
tative verdict  on  88.5$ — that  is,  giving  the  article  on  trial  the 
benefit  of  possibilities  in  both  the  cases  alike — from  88.6$  of  in- 
soluble fat  acids  only  1.43$  of  foreign  fat  in  the  total  fat  would 
be  declared.  And  a  logically  guarded  report  could  state  that, 
from  the  evidence  of  88.6$  of  insoluble  fat  acids,  it  appears  that 
an  adulteration  of  foreign  fat  has  been  made,  in  quantity  from 
about  1.5  to  about  23  per  cent.,  and  probably  near  13  per  cent. 

In  order  to  reach  a  secure  conclusion  respecting  the  fact  of 
adulteration  in  cases  of  admixture  of  foreign  fats  with  large  pro- 
portions of  butter  fat,  and  in  order  to  give  the  percentage  of 
foreign  fat  within  limits  brought  as  near  each  other  as  possible, 
more  than  one  of  the  estimations  (Hehner's,  Reichert's,  Kottstor- 
fer's)  should  be  made.  The  three  estimations,  with  determina- 
tion of  the  specific  gravity  of  the  fat  as  a  fourth,  furnish  together 
a  body  of  evidence  more  trustworthy  in  cases  of  difficulty  as  to 
the  fact  of  adulteration,  and  more  exact  respecting  percentages, 
than  can  be  drawn  from  any  smaller  number  of  determinations. 
Still  other  determinations,  as  those  of  melting  and  congealing 
points,  and  the  quantity  of  casein,  sometimes  give  additional  ad- 
vantage. In  case  of  doubt  every  means  of  investigation  should 
be  used.  And  all  important  estimations  should  be  obtained  in 
triplicate  or  duplicate  results. 


312  FORMIC  ACID. 

FORMIC  ACID.— Ameisensaure.  CH2O2rz:46.  Hydro- 
gen-carboxyl,  H.CO2H,  the  first  member  of  the  fatty  acid 
series,  CnH2n+1CO2H. — Obtained  by  distilling  the  bodies  of 
ants  with  water.  A  constituent  of  the  exudate  carried  with  the 
stings  of  insects  and  of  stinging  nettles.  A  product  of  nume- 
rous organic  reactions,  including  a  rapid  action  of  alkalies  upon 
chloral,  and  a  feebler  action  of  alkalies  upon  chloroform,  also  the 
action  of  potassium  upon  carbon  dioxide  and  water,  or  of  hot 
potassium  hydrate  solution  upon  carbon  monoxide.  Prepared  by 
distillation  from  oxalic  acid  and  glycerin.  A  common  result  of 
destructive  distillation. 

Formic  acid,  when  free  and  not  dilute,  is  recognized  by  its 
odor  and  irritating  effect  on  the  skin  (J).  Tests  of  identification 
are  obtained  in  the  color  with  ferric  salt,  the  precipitates  with 
lead  acetates  and  alcohol,  the  reduction  of  silver  or  mercury,  and 
the  generation  of  carbon  monoxide  with  sulphuric  acid  (d). 
/Separations  are  made  by  distilling  formate  with  phosphoric  acid, 
and  by  the  insolubility  of  lead  or  calcium  formate  in  alcohol  (e). 
Estimations  are  conducted  acidimetrically,  by  weight  of  lead 
formate,  and  by  weight  of  mercury  reduced  (f ).  Certain  im- 
purities are  liberated  by  holding  calcium  formate  in  alcohol  (g). 

a. — Formic  acid  is  a  colorless  liquid,  of  specific  gravity  of 
1.221  at  20°  C.,  boiling  at  100°  C.,  the  T7.5  per  cent,  acid  at 
107.1°  C.,  and  crystallizing,  when  pure,  below  0°  C.  Metallic 
formates  heated  to  decomposition  do  not  form  a  carbonaceous 
residue. 

J. — The  odor  of  formic  acid  is  pungent,  in  proportion  to  the 
concentration  of  its  aqueous  solution,  the  vapor  from  the  strong 
acid  having  a  slightly  suffocating  effect  reminding  of  sulphurous 
acid.  The  taste  is  purely  acidulous.  The  effect  is  irritating,  the 
strong  acid  causing  burning  and  itching  of  the  skin,  a  biting  sen- 
sation of  the  tongue,  and  a  tingling  of  the  nostrils. 

c. — Formic  acid  is  miscible  in  all  proportions  with  water  and 
with  alcohol.  The  metallic  formates  are  generally  soluble  in 
water  and  but  little  soluble  in  alcohol.  The  normal  metallic 
formates  mostly  exhibit  a  neutral  reaction  with  litmus-paper ;  the 
normal  lead  formate  being  neutral,  and  the  basic  lead  formate  al- 
kaline in  reaction.  The  formates  crystallize  readily. 

d. — Ferric  chloride,  in  a  neutral  solution  of  alkali  formate, 
forms  ferric  formate,  of  red  color,  and  precipitated  on  boiling,  a 
reaction  closely  resembling  that  of  acetic  acid. — Normal  lead 


FORMIC  ACID.  313 

acetate  precipitates  concentrated  solution  of  an  alkali  formate, 
the  normal  formate  of  lead  being  soluble  in  65  parts  of  cold 
water.  By  adding  to  the  mixture  twice  its  volume  of  alcohol 
the  precipitation  is  much  increased.  If  basic  lead  acetate  solu- 
tion be  saturated  with  alcohol  it  serves  to  precipitate  formic  acid, 
free  or  combined,  quite  completely,  as  the  basic  formate  of  lead 
is  very  little  soluble  in  alcohol  of  moderate  strength.  The  pre- 
cipitate of  lead  formate  dissolves  freely  in  hot  water,  and  on  cool- 
ing the  solution  needle-form  crystals  of  lead  formate  are  obtained, 
more  perfectly  after  several  hours. — Silver  nitrate  solution  gives 
a  white,  crystalline  precipitate  of  silver  formate,  only  in  quite  con- 
centrated solutions.  On  standing  or  warming  the  precipitate 
blackens  by  reduction  to  metallic  silver.  In  more  dilute  solutions 
the  metallic  silver  is  the  lirst  form  of  the  precipitate,  and  best 
obtained  in  neutral  or  feebly  acidulous  solution,  free  ammonia 
being  avoided.  Reduction  by  vapor  of  formic  acid  is  to  be 
adopted  if  non-volatile  reducing  agents  are  liable  to  be  present, 
and  is  accomplished  by  slightly  acidulating  the  mixture  with 
sulphuric  acid  and  immersing  the  test-tube  for  some  time  in 
boiling  water,  while  a  disk  of  filter-paper  previously  wetted  or 
crossed  with  solution  of  silver  nitrate  is  bound  over  the  mouth  of 
the  tube. — Mercurous  nitrate  gives  a  precipitate  of  mercurous 
formate,  soluble  in  500  parts  of  water.  Reduction  to  metallic 
mercury  is  obtained  on  standing  twenty-four  hours,  more  readily 
on  warming. 

Concentrated  sulphuric  acid,  at  a  gentle  heat,  resolves  formic 
acid  into  carbon  monoxide  and  water  (OH2O2— H2O-|-CO). 
The  formic  acid  or  its  salt  is  warmed  with  about  three  times  its 
volume  of  the  sulphuric  acid.  With  a  considerable  quantity  the 
resulting  gas  may  be  burned  at  the  mouth  of  the  test-tube,  with 
a  blue  flame.  No  carbon  dioxide  is  obtained,  carbonates  being 
absent — a  difference  from  oxalic  acid.  Heated  with  strong  alkali, 
in  the  air,  formate  is  changed  to  oxalate. — Ethyl  formate  is  de- 
veloped by  distilling  a  dry  formate  with  about  an  equal  quantity 
of  alcohol  and  a  double  quantity  of  sulphuric  acid,  undiluted. 
The  ester  has  a  characteristic  fragrance,  sajd  to  resemble  that  of 
peach-kernel — not  sharply  distinguished  from  esters  of  homolo- 
gous acids  as  obtained  in  qualitative  tests. 

e. — Separations. — Free  formic  acid  may  be  separated  from 
water  and  other  non-acidulous  volatile  bodies  by  neutralizing  with 
fixed  alkali  and  evaporating  to  dryness  on  the  water-bath.  From 
the  residue,  or  any  portion  of  formate,  by  adding  phosphoric 
acid  and  distilling  at  100°  C.  or  a  little  above.  If  sulphuric  acid 


3  H  FUSEL   OIL. 

be  used  instead  of  phosphoric  it  must  be  well  diluted,  and  the 
dilution  maintained  by  adding  water  from  time  to  time,  long  dis- 
tillation being  now  required. — From  acetic  acid  free  formic  acid 
may  be  separated  by  digesting  with  enough  lead  oxide  to  cause  a 
permanently  alkaline  reaction,  evaporating  to  dryness,  and  ex- 
hausting the  residue  with  alcohol.  The  filtrate  will  contain  the 
acetic  acid  as  lead  basic  salt,  and  the  residue  will  contain  the 
formic  acid  in  combination,  from  which  it  can  be  recovered  by 
distilling  from  phosphoric  acid  or  by  thorough  treatment  with 
hydric  sulphide  gas  and  following  filtration.  Instead  of  lead 
oxide,  calcium  carbonate  or  magnesium  oxide  may  be  employed, 
recovering  the  formic  acid  by  distilling  from  phosphoric  acid. 

f. —  Quantitative. — Free  formic  acid  may  be  estimated  volu- 
metrically  by  titrating  with  alkali,  using  litmus  or  phenol-phthal- 
ein  as  an  indicator. — -The  lead  formate  obtained  by  precipitation 
with  lead  normal  acetate  and  alcohol,  as  directed  under  d,  may 
be  washed  with  alcohol,  dried,  and  weighed  as  normal  lead  for- 
mate.— In  a  mixture  of  formic  and  acetic  acids  the  formic  acid  is 
capable  of  estimation  by  its  reduction  of  mercury.  The  mixture 
is  digested  some  time  with  an  excess  of  yellow  mercuric  oxide, 
the  washed  residue  treated  with  dilute  hydrochloric  acid  to  re- 
move the  remaining  oxide,  and  the  metallic  mercury  gathered, 
washed,  and  weighed.  HgO  +  CH4O  =  Hg  +  CO2  +  H2O. 
Hg  :  CH4O  ::  199.7  :  46  ::  1  :  0.2303. 

g. — Impurities  of  acetic,  hydrochloric,  nitric,  or  other  acids 
forming  calcium  salts  soluble  in  alcohol  may  be  found  by  digest- 
ing the  acid  mixture  with  excess  of  calcium  carbonate,  evaporat- 
ing to  dryness,  and  treating  with  alcohol,  when  the  filtrate  will 
contain  the  calcium  salts  of  the  acids  mentioned. 

FUSEL  OIL. — Fuselol.  Huile  de  pommes  de  terre  (po- 
tato oil). — The  sum  of  the  heavy  alcohols  obtained  as  a  by-pro- 
duct in  the  manufacture  of  ethyl  alcohol  in  its  ordinary  forms. 
A  portion  of  higher-boiling  distillate  received  after  distillation 
of  commercial  alcohol  or  distilled  spirits.  A  variable  body  of 
amyl  alcohols  with  smaller  proportions  of  adjacent  alcohols  of 
the  CnH2n  2O  series,  as  products  accompanying  ethyl  alcohol  in 
the  common  alcoholic  fermentation.  Obtained  in  the  fermenta- 
tion of  potatoes,  indian  corn,  marc  of  grapes,  and  in  smaller 
quantities  by  the  fermentation  of  other  materials  used  as  sources 
of  sugar.  Fusel  oils  from  their  several  sources  differ  from  each 
other  in  composition,  but  amyl  alcohols  form  by  far  the  larger 
part  of  all  of  them.  Acids  of  the  CnH2nO2  series  are  found  in 


FUSEL   OIL.  315 

fusel  oils,  where  they  are  formed  by  oxidation  of  the  alcohols. 
Ethereal  salts  occur  by  action  of  fusel  oil  acids  upon  fusel  oil 
alcohols  and  upon  ethyl  alcohol,  as  a  result  of  "  ageing." 

The  alcohols  of  fermentation,  found  in  fusel  oils,  are  chiefly 
as  follows : 


Per  cent, 
by  vol. 

Boiling, 

C. 

Spec, 
grav. 

27.51 

Inactive    amyl    alcohol,    iso- 
butyl  carbinol  (CH8)2  .  CH  .  CHa  CH2OH  . 

131.4° 

0.812 

13.0   ) 
6.01  ] 
5.01 

Active  amyl  alcohol,  second- 
ary-butyl carbinol  CH3.C2H6.CH.CH2OH..  . 
Iso-  butyl  alcohol,  propyl  car- 
binol    (CHs)2.CH.CHaOH  

128° 
108.4° 

0.808* 
0.802 

6.5'(?) 
Traces  . 
3.0' 
151    (ft 

Normal  butyl  alcohol  CH3.CH2.CH2.CH2OH  .  . 
Tertiary  butyl  alcohol  (CH3)3.COH  
Normal  propyl  alcohol  CH3.CH2.CH.,OH  
Secondary  propyl  alcohol        CH3  CH(CH3)OH 

116° 
84° 
97.4° 

82  8° 

0.810 
0.779 

0.807 
0  788 

A  primary  hexyl  alcohol.   ...  CeHi3OH  .        

150° 

The  identification  of  several  of  the  alcohols  given  above  is 
not  well  established.  The  isomerides  of  different  fusel  oils  are 
not  the  same.  Rabuteau  (loo.  cit.)  obtained  17  per  cent,  of  pro- 
ducts boiling  above  132°  C.,  and  including  some  amyl  alcohols. 
ORDONNEAU  (1886 :  JRep.  anal.  Chem.)  obtained  from  wine  bran- 
dy twenty-five  years  old  the  following :  normal  propyl  alcohol, 
0.040$  ;  normal  butyl  alcohol,  0.218$  ;  normal  [!J  amyl  alcohol, 
0.084$;  normal  hexyl  alcohol,  0.0006$;  normal  heptyl  alcohol, 
0.0015$  ;  propionic,  butyric,  and  caprilic  ethers,  0.004$  ;  oenan- 
thic  ether,  about  0.004$ ;  acetic  ether,  0.035$ ;  ethylaldehyde, 
0.003$;  acetal,  0.035$;  amine  bases,  0.004$.  The  same  author 
states  that  alcohol  from  maize,  beets,  or  potatoes  contains  iso- 
butyl  instead  of  normal  butyl  alcohol,  and  contains  amyl  and 
propyl  alcohols,  and  pyridine,  probably  collidine.  Wine  yeast 
(elliptic)  produces  normal  butyl  alcohol;  beer  yeast  (globular)  no 
butyl  alcohol.  Except  the  uncertain  report  of  secondary  propyl 
alcohol,  above  quoted,  and  the  traces  of  tertiary  butyl  alcohol,  the 
alcohols  found  in  fusel  oil  are  primary,  and  therefore  capable  of 
forming  acids  without  breaking  up.4 

1  KABUTEAU,  1878:  Compt.  rend.,  87,  501;  Jour.  Chem.  Soc.,  36,  36. 

2  LE  BEL,  1873:  Ber.  d.  chem.  Ges.,  6,  1362. 

3  FAGET:  Liebig's  Annalen,  88,  32o— normal  hexyl  alcohol. 

4  Of  pentyl  alcohols,   CtHuOH,   eight  are  possible,  and  seven  are  known: 
three  primary  alcohols,    three   secondary  alcohols,  and  one  tertiary  alcohol. 
There  are  four  butyl  alcohols,  C4H»OH,  two  primary  and  two  secondary,  all 


3i6  FUSEL   OIL. 

The  fusel  oil  acids  are  not  found  in  quantities  sufficient  for 
their  satisfactory  separation.  Of  ethereal  salts,  ethyl  salts  have 
been  mainly  found,  instead  of  amyl  salts,  in  fusel  oils.  Ethyl 
alcohol  is  retained  in  various  quantities,  limited  by  present  Eng- 
lish excise  law  to  be  below  15  per  cent,  of  commercial  fusel  oils. 

a. — Fusel  oils  are  received  by  distillations  beginning  at  105° 
to  125°  G.,  and  ending  at  132°  to  137°  C.  Between  105°  and 
120°  C.  the  most  of  the  iso-butyl  alcohol  is  obtained ;  between 
128°  and  132°  C.  the  amyl  alcohols  are  mostly  distilled. 

b. — In  physiological  effects  the  fusel  oils  have  a  stifling, 
harsh,  spirituous  odor,  quite  characteristic  and  subject  to  differ- 
ences which  reveal  to  the  expert  the  source  of  the  fusel  oil. 
Even  a  slight  inhalation  excites  coughing.  Objectionable  pro- 
portions of  fusel  oil  in  alcoholic  liquors  are  recognized  by  first 
evaporating  off  the  ethyl  alcohol  and  obtaining  the  odor  of  the 
warmed  residue.  For  the  U.  S.  Ph.  test  of  "  alcohol "  it  is  pre- 
scribed that  "  if  mixed  with  its  own  volume  of  water  and  one- 
fifth  its  volume  of  glycerin,  a  piece  of  blotting-paper  on  being 
wet  with  the  mixture,  after  the  vapor  of  alcohol  has  wholly  dis- 
appeared, should  give  no  irritating  or  foreign  odor  (fusel  oil)." 
"  A  little  [rectified  spirit]  rubbed  on  the  back  of  the  hand  leaves 
no  unpleasant  smell  after  the  spirit  has  evaporated  "  (Br.  Ph.) 

In  their  effects  on  the  system  the  alcohols  of  the  CbH2n+2O  se- 
ries have  an  intensity  which  increases  with  the  molecular  weight. 
RABUTEAU  (1870),  mainly  from  experiments  with  frogs,  estimated 
the  intensities  of  effect  of  ethyl,  butyl,  and  amyl  alcohols  to  be, 
respectively,  as  1,  5,  and  15.  Dr.  B.  W.  RICHARDSON'  states 
that  the  action  of  amyl  alcohol  is  that  of  butyl  alcohol  intensified. 
In  the  third  stage  of  the  action  there  are  pronounced  tremors  of 
regular  recurrence,  reduction  of  temperature,  and  profound  coma. 
Recovery  requires  sometimes  two  or  three  days.  In  recovery 
the  restoration  of  the  temperature  is  delayed  longest.  After 
death  from  amyl  alcohol  the  blood  is  excessively  venous. 

c. — /Solubilities. — The  amyl  alcohols  of  fusel  oil  are  said  to 
dissolve  in  about  40  parts  of  cold  water.  According  to  BAL- 

known.  The  two  possible  propyl  alcohols,  C3H7OH,  are  included  in  the  list 
above.  Of  the  seventeen  hexyl  alcohols,  isomerides  of  C6H13OH,  eight  are 
known  at  present,  four  being  primary.— It  is  evident,  upon  a  very  simple  ac- 
quaintance with  chemical  law,  that  there  can  be  but  one  ethyl  alcohol,  in  what- 
ever mixture  it  be  found.  Differences  in  the  physiological  effects  of  various  al- 
coholic beverages  are  not  due  to  any  difference  in  the  ethyl  alcohol  contained 
therein. 

1 1875 :  Cantor  Lectures,  London. 


FUSEL    OIL.  317 

BIANO  (1876 ')  the  inactive  amyl  alcohol  of  fusel  oil  is  soluble  in 
about  50  parts  of  water  at  14°  C.,  and  less  soluble  in  water  at 
50°  C.  Iso-butyl  alcohol  is  soluble  in  10  parts  of  water  at  15°  C. 
One  part  of  inactive  amyl  alcohol  takes  up  about  0.08  parts  of 
water ;  one  part  of  iso-butyl  alcohol,  about  0.15  parts  of  water. 
Fusel  oil  is  freely  soluble  in  ether,  chloroform,  and  the  other  im- 
miscible solvents  of  general  use.  Of  the  amylsulpJiates  of  barium, 
that  formed  from  inactive  amyl  alcohol  is  two  and  a  naif  times 
less  soluble  in  water  than  is  that  from  active  amyl  alcohol — a  dif- 
ference made  available  for  separation  of  these  isomers. 

d. — In  the  qualitative  identification  of  fusel  oil  the  odor,  and 
the  effect  of  inhalation,  are  the  means  in  most  common  use.  In 
testing  fusel  oil  in  liquors  or  commercial  alcohol  the  ethyl  alco- 
hol is  made  to  evaporate  before  obtaining  the  odor.  The  Br. 
Ph.  and  U.  S.  Ph.  directions  for  examination  by  odor  are  given 
under  b.  Separation  by  an  immiscible  solvent,  as  described  un- 
der £,  may  be  adopted  preparatory  to  any  qualitative  examina- 
tion. In  ordinary  analyses  of  alcoholic  liquors  or  commercial 
alcohols,  the  ethyl  alcohol  has  to  be  separated  by  careful  distilla- 
tion for  the  estimation  of  "  strength,"  and  the  residue  of  such 
distillation,  while  warm,  is  to  be  examined  for  odor. 

Concentrated  sulphuric  acid,  on  contact  with  fusel  oils,  en- 
ters into  formation  of  amylsulphuric  acids,  HC5HnSO4,  present- 
ing a  red  color.2  According  to  YITALI  (loo.  cit.\  when  the  sul- 
phuric acid  is  added  to  a  smaller  quantity  of  fusel  oil  the  color 
is  red,  growing  brown-red  on  standing  and  on  heating.  Equal 
volumes  of  the  amyl  alcohols  and  the  sulphuric  acid  give  a  dark 
and  dull  red  color ;  but  with  an  excess  of  the  fusel  oil  differ- 
ent tints  are  obtained,  cherry-red,  violet,  azure-blue,  and  green, 
in  the  order  of  the  increasing  excess  of  fusel  oil.  When  to  a 
drop  or  two  of  sulphuric  acid,  on  a  white  porcelain  surface,  an 
equal  volume  of  the  fusel  oil  is  first  added,  and  then  additional 
portions  of  the  latter,  cherry-red  and  violet  tints  are  obtained, 
and  at  the  proportions  of  five  or  six  volumes  of  the  fusel  oil  the 
azure-blue  color  is  reached.  The  addition  of  ether  to  the  colored 
mixture  increases  the  brilliancy  of  the  tints. 

The  test  may  be  applied  to  the  residue  left  after  evaporation 
of  a  chloroformic  or  ethereal  solution,  obtained  by  shaking  out 

1  Ber.  d.  chem.  Ges.,  9.  1437. 

SPELLETAN,  1825:  Ann.  Ghim.  Phys.,  [2],  30,  221.  Amylsulphuric  acid 
of  iso-butyl  carbinol  (inactive  amyl  alcohol),  CAHOURS,  1839:  Ann.  Chem.Phar., 
30,  291.  As  a  color  test  for  fusel  oil,  further,  VJTALI,  1884:  Archiv  der  Phar., 
[3],  21,  964;  Zeitsch.  anal.  Chem.,  23,  426;  Analyst,  9,  196. 


3i8  FUSEL    OIL. 

as  stated  under  «,  and  as  so  applied  the  test  is  trustworthy  for 
negative  results  showing  the  absence  of  material  proportions  of 
fusel  oil.  But  inasmuch  as  numerous  non-volatile  bodies  give 
colors  with  sulphuric  acid,  an  indication  of  the  presence  of  fusel 
oil  should  be  verified,  in  this  test,  by  applying  it  to  a  fractional 
distillate  from  the  liquor  or  commercial  alcohol  under  examina- 
tion— a  distillate  obtained  between  about  120°  and  134°  C. 

For  the  qualitative  use  of  MARQUARDT'S  plan  of  separating 
amyl  alcohols  directions  are  given  below  under  f.  This  method 
is  very  delicate.  The  odor  of  the  valeric  acid  is  highly  distinc- 
tive.— The  reaction  of  JORISSEN,  obtained  by  mixing  with  a  lit- 
tle colorless  aniline  oil  and  a  few  drops  of  sulphuric  acid,  for  a 
fine  red  color,  depends  on  the  presence  of  furfurol  (aldehyde  be- 
tween furfuryl  alcohol  and  pyromucic  acid)  present  in  fusel  oils." 
— SEVALLE  (1881)  determines  the  presence  of  fusel  oil  by  turbi- 
dity of  its  alcoholic  mixture  when  heated. — TRAUBE  2  tests  brandy, 
after  dilution  to  about  20  per  cent,  of  strength,  by  the  height  to 
which  the  liquid  rises  in  a  capillary  tube,  as  compared  with  a 
pure  spirit  of  the  same  strength. — The  etherification  of  amyl  al- 
cohols, to  form  esters  of  acetic  acid,  has  been  included  among 
methods  for  recognition.  The  liquid  is  warmed  or  distilled 
with  alkali  acetate  and  sulphuric  acid.  The  odor  of  amyl  acetate 
is  that  of  pears.  This  odor,  however,  is  quite  liable  to  be  covered 
by  that  of  acetic  acid  or  ethyl  acetate,  so  that  caution  should  be 
observed  in  interpretation  of  the  result. 

e. — The  separation  of  fusel  oil  by  distillation  gives  prac- 
tically conclusive  results,  but  is  certainly  not  without  waste.  Sep- 
aration by  immiscible  solvents  is  generally  employed.  BETELLI* 
adds  to  a  certain  quantity  of  the  commercial  alcohol  six  or  seven 
times  its  volume  of  water,  and  shakes  with  chloroform  enough 
to  make  after  subsiding  a  very  small  layer,  which  is  drawn  off 
and  evaporated  for  test  of  the  residue.  With  only  5  or  6  c.c.  of 
the  alcohol,  and  15  to  20  drops  of  the  chloroform,  0.05  per  cent, 
of  fusel  oil  was  detected,  the  final  test  being  that  of  etherification 
to  amyl  acetate  ("  pear  oil  " )  by  digesting  the  residue  with  al- 
kali acetate  and  sulphuric  acid.  Before  applying  the  immiscible 
solvent  it  is  proper  to  reduce  the  concentration  of  the  ethyl 

1  FORESTER,  1882:  Ber.  d.  chem.  Ges.,  15,  230. 

2 1886:  Ber.  d.  chem.  Ges.,  19.  892;  Jour.  Chem.  Soc.,  50,  743.  Follows  a 
report  on  relation  between  capillarity  and  molecular  weight,  and  on  specific 
capillarity,  1885:  Jour,  prakt.  Chem.,  [2],  31,  177,  514;  Jour.  Chem.  Soc.,  48, 
866,  1033. 

3 1875:  Ber.  d.  chem.  Oes.,  8,  72;  Zeitsch.  anal.  Chem.,  14,  197. 


FUSEL    OIL.  319 

alcohol,  either  by  distilling  it  off  or  by  adding  water.     See  the 
directions  given  below  under/*. 

f. —  Quantitative. — For  the  estimation  of  fusel  oil  the  method 
of  MAKQUARDT  '  is  here  given :  The  fusel  oil  is  separated  from  a 
diluted  alcoholic  liquid  by  shaking  out  with  chloroform ;  the 
amyl  alcohol  is  oxidized  to  valeric  acid;  the  acid  is  taken  up 
by  barium  carbonate,  and  the  barium  salt  is  estimated,  to  repre- 
sent the  quantity  of  amyl  alcohol  oxidized.  Of  the  alcoholic 
liquid  under  examination  150  grams  are  to  be  diluted  with  an 
equal  volume  of  water,  and  agitated  with  50  c.c.  of  chloroform 
(of  ascertained  purity)  for  about  a  quarter  of  an  hour.  The 
aqueous  layer  is  separated  and  again  extracted  with  50  c.c.  of 
chloroform  for  the  same  length  of  time.  The  operation  is  re 
peated  the  third  time.  The  united  portions  of  chloroform  are 
treated,  in  a  strong  flask,  with  a  solution  of  5  grams  dichromate 
in  30  grams  of  water,  and  2  grams  of  sulphuric  acid,  digesting 
for  about  six  hours  with  frequent  agitation  while  the  flask  is  well 
corked.  The  contents  of  the  flask  are  then  distilled  until  about 
20  c.c.  remain,  when  this  residue  is  diluted  by  addition  of  about 
80  c.c.  of  water,  and  again  distilled  until  only  about  5  c.c.  remain. 
The  entire  distillate  is  then  digested  with  heat  for  half  an  hour 
with  barium  carbonate,  an  erect  condenser  being  employed  to 
return  the  distillate  to  the  flask.  The  chloroform  is  then  sepa- 
rated by  distillation,  and  the  aqueous  residue  concentrated  to  a 
volume  of  5  c.c.  The  excess  of  barium  carbonate  is  filtered  out, 
and  the  filtrate  with  the  washings  evaporated  in  a  weighed  dish 
on  a  water- bath  to  dry  ness.  The  residue  is  weighed,  and  after- 
wards dissolved  in  water  and  a  few  drops  of  nitric  acid,  and 
made  up  with  water  to  100  c.c.,  of  which  50  c.c.  are  taken  to  es- 
timate the  barium,  and  50  c.c.  to  estimate  the  chlorine  (derived 
from  the  chloroform  by  action  of  the  dichromate).  The  quantity 
of  barium  combined  with  the  chlorine  is  calculated,  and  deducted 
from  the  total  barium  in  the  50  c.c.  From  the  remaining  quan- 
tity of  barium  the  quantity  of  valeric  acid  is  calculated,  and 
from  this  the  quantity  of  amyl  alcohol.  Then  BaSO4  :  2C5H12O 

::  232.8  :  176  ::1  :  0.7560.     And  the  weight  of  barium  sulphate 

X  0.756  =  the  weight  of  amyl  alcohol. 

For  exact  results  the  chloroform  used  is  to  be  purified  by 
subjecting  it  to  the  operation  as  described — treatment  with  solu- 
tion of  dichromate  and  sulphuric  acid,  distillation,  digestion  of 

'L.  MARQUARDT,  1882:  Ber.  d.  chem.  Ges.,  15,  1370,  1661;  Analyst.  8, 
106;  Jour.  Soc.  Chem.  Ind.,  I,  331,  377;  Jour.  Chem.  Soc.,  42,  1235,  1327.  A 
favorable  report  upon  Marquardt's  method  is  given  by  G.  LUNGE,  V.  MEYER, 
and  E.  SCHULZE,  1884:  Chem.  Cent.,  p.  854;  Jour.  Chem.  Soc.,  48,  708. 


320  GALLIC  ACID. 

the  distillate  with  barium  carbonate,  and  redistillation.  To  pu- 
rify ordinary  chloroform  it  is  necessary  to  repeat  the  process 
several  times. 

In  the  qualitative  use  of  the  test  30  to  40  grams  of  the  spirit 
are  diluted  with  water  so  as  to  contain  12  to  15  per  cent,  of  al- 
cohol, and  the  liquid  shaken  up  with  15  c.c.  of  pure  chloroform. 
The  chloroform  solution  is  washed  with  about  an  equal  volume 
of  water,  and,  after  the  latter  has  separated,  is  evaporated  to  dry- 
ness.  To  the  residue  are  added  a  little  water,  one  or  two  drops  of 
sulphuric  acid,  and  permanganate  of  potassium  enough  to  give  a 
red  color  after  24  hours. 

The  estimation  of  fusel  oil  by  measurement  of  the  increase 
of  volume  of  the  chloroform  layer,  after  shaking  out,  making 
comparison  with  a  standard  spirit,  has  been  undertaken  by  B. 
ROSE,  and  advanced  by  Messrs.  STUTZER  and  REITMAIR,'  but  the 
method  is  not  well  sustained.8 

The  quantities  of  fusel  oils  present  in  alcoholic  liquors  have 
not  been  generally  obtained  upon  trustworthy  data.  In  certain 
whiskeys  there  were  obtained,  in  the  analyses  of  DR.  DupRE,from 
0.18  to  0  24  parts  of  amyl  alcohol  to  100  parts  of  ethyl  alcohol. 
IS".  P.  HAMBERG  3  has  given  figures  for  the  fusel  oil  in  beer  as 
follows  :  1.14  gram  of  fusel  oil  in  100  liters  of  the  beer,  or  about 
0.00114  per  cent. 

GALLIC  ACID.-C7H605  =  C6H2(CO2H)(OH)3  =  170.  A 
trihydroxy-benzoic  acid  [CO2H  :  OH  :  OH  :  OH  =  1 :  3  :  4  :  5]. 
Gallussaure. — Found  in  nutgalls,  sumach,  tea,  and,  accompany- 
ing tannins,  in  a  large  number  of  plants.  Gallic  anhydride,  as 
digallic  acid,  occurs  in  gallotannic  acid,  and  gallic  acid  is  a  natu- 
ral fermentation  product  of  certain  glucoside-tannins.  It  is  in 
use  in  medicine,  as  a  reducing  agent  in  photography,  and  in 
hair  dyes.  It  is  not  a  tanning  agent.  Gallotannic  acid,  in  the 
human  body,  is  soon  converted  into  gallic  acid.  The  gallic  acid 
of  commerce  is  wholly  manufactured  from  the  tannin  of  galls. 

Gallic  acid,  as  a  separate  solid,  is  identified  by  its  sensible 
properties  and  decomposition  products  (a);  in  solution,  by  its 

1  Summary  by  UFFELMANN,  1886:  Ding.  pol.  Jour.,  261,  439;  Jour.  Chem. 
Soc.,  SO,  1079.  B.  ROSE,  1885:  Archiv  d.  Phar.,  [3],  23,  62. 

*  LUNGE,  MEYER,  and  SCHULZE,  1884:  Jour.  Chem.  Soc.,  48,  709. 

3 1885:  Trans.  Royal  Acad.  Stockholm;  Schmidt's  Jahrbucher  der  Medicin, 
201,  27. 


GALLIC  ACID.  321 

reactions  with  iron  salts,  lime,  and  antimony,  and  its  reducing 
power  (d).  It  is  distinguished  from  tannins  by  non-precipitation 
of  gelatin,  alkaloids,  and  antimony  in  presence  of  ammonium 
chloride.  Separations  from  tannins,  various  acids,  and  from 
metals  are  indicated  in  e,  methods  of  estimation  in  f,  and  tests 
for  purity  in  g. 

a,  5.— Gallic  acid  crystallizes,  as  C7H6O5.H2O  =  188  (9.5# 
crystal  water),  in  gray- white  silky  needles,  or  triclinic  prisms, 
odorless,  of  an  astringent  and  slightly  acidulous  taste,  and  acid 
reaction.  The  crystals  are  permanent,  but  lose  all  their  water  at 
100°  C.  If  the  dry  acid  be  gradually  heated,  in  a  glass  tube,  at 
210°' to  215°  C.  (4rlO°-1190F.),  a  white  or  yellowish- white  subli- 
mate of  pyrogallol  appears,  in  droplets,  crystallizing  on  cooling : 
C7II6O5  =  C6H6O3  +  CO2 .  A  dark  residue  remains.  Heated 
quickly,  in  a  porcelain  capsule,  at  about  250°  C.  (482°  F.),  meta- 
gallic  acid,  C6H4O2,  is  formed,  iri  a  black  lustrous  residue,  sol- 
uble in  strong  alkali  solution,  with  dark-brown  color.  Heated 
very  gradually,  with  concentrated  sulphuric  acid,  in  a  test-tube, 
to  about  150°  C.  (302°  F.),  the  mass  turns  wine-red  to  carrnine- 
red.  If  now  cooled  and  poured  into  water,  the  latter  will  be 
colored  yellow-brown,  and  a  red-brown  precipitate  of  ruh'irallol 
(rufigallic  acid)  partly  crystalline  (in  rhombohedrons)  will  ap- 
pear. If  the  precipitate  be  washed  and  dried,  then  treated  with 
very  strong  potassium  hydroxide  solution,  a  blue  color  changing 
to  violet  is  obtained.  Traces  of  rutigallol  may  be  taken  up  with 
acetic  ether.  Baryta  water  also  gives  a  blue  color  with  rufigal- 
lol.  If  gallic  acid  be  warmed  with  potassium  hydroxide,  tanno- 
melanic  acid,  of  a  black  color,  is  produced.  All  alkaline  solu- 
tions of  gallic  acid  soon  darken  in  the  air. 

c. — Gallic  acid  is  soluble  in  100  parts  of  cold  or  3  parts  of 
boiling  water,  the  hot-saturated  solution  giving  abundant  crys- 
tals on  cooling.  It  is  freely  soluble  in  alcohol,  soluble  in  39 
parts  of  absolute  ether,  freely  soluble  in  acetic  ether,  scarcely  at 
all  soluble  in  chloroform,  benzene,  or  benzin.  Gallic  acid,  by 
structure  monobasic,  is  stated  to  form  three  classes  of  metallic 
salts  by  the  displacing  of  one,  two,  and  three  atoms  of  its  hy- 
drogen, only  the  alkali  salts  being  soluble  in  water.  Aqueous 
•solutions  of  the  acid  soon  decompose,  with  deposition  of  humus- 
like  products. 

d. — Solution  of  lime,  added  to  an  alkaline  reaction,  causes  a 
white  turbidity,  changing  to  blue,  later  to  green.  Acetate  of 
lead  gives  an  abundant  white  precipitate,  not  especially  char- 
acteristic. Ferric  salts,  and,  more  perfectly,  the  ferroso-ferric 


322  GALLIC  ACID. 

solutions,  with  free  gallic  acid,  give  a  deep  blue  or  blue-black  pre- 
cipitate, decolored  by  boiling  (with  reduction  of  ferric  to  ferrous 
salt),  and  decolored  by  sufficient  acetic  acid  or  by  excess  of  al- 
kalies. Tartrate  of  antimony  and  potassium  causes  a  pre- 
cipitate, which,  in  distinction  from  gallotannin,  is  prevented 
or  dissolved  by  ammonium  chloride.  Precipitates  are  not  ob- 
tained with  gelatin,  or  albumen,  or  starch,  or  with  the  alkaloids 
(all  distinctions  from  gallotannin). 

Lead  acetate  with  free  gallic  acid  gives  a  bulky  white  pre- 
cipitate, which  by  warming  condenses  to  a  heavy  powder,  easily 
washed.  The  fresh  precipitate,  with  sodium  or  potassium  hy- 
droxide, turns  red. 

As  a  reducing  agent  gallic  acid  is  in  general  only  a  very  lit- 
tle less  forcible  than  tannin.  Permanganate  is  promptly  de- 
colored by  gallic  acid.  Fehling's  solution  is  turned  from  blue  to 
yellow-brown  at  once,  but  the  cuprous  precipitate  is  very  slowly 
obtained  after  heating  for  some  minutes.  Silver  nitrate  is  slowly 
reduced,  after  warming,  sometimes  in  part  as  a  mirror.  Molyb- 
date  of  sodium  or  ammonium  reacts  as  with  gallotannin.  Ferric 
salts  are  partly  reduced  by  boiling  with  gallic  acid. 

e. — Gallic  acid  may  be  separated  from  tannin  by  full  precipi- 
tation of  .the  latter  with  cinchonine  sulphate  and  filtration.  By 
precipitation  with  some  excess  of  gelatin,  filtering  (concentrat- 
ing the  filtrate  if  need  be),  adding  alcohol  enough  to  throw  down 
all  the  gelatin,  and  filtering  again.  Also  by  digestion  with 
rasped  hide.  From  the  fruit  acids,  with  tannin,  if  it  be  present, 
by  calcium  acetate,  acetic  acid  and  alcohol,  or  by  acetic  ether  so- 
lution. From  all  acids  not  precipitated  with  lead  acetate  by  this 
reagent,  as  above,  separating  the  lead  from  the  precipitate  by 
treatment  with  hydrosulphuric  acid  and  filtration.  Recent  lead 
hydrate  removes  all  but  a  trace  of  free  gallic  acid.  From  its 
iron  salts  it  is  obtained  by  treatment  with  oxalic  acid  to  fully 
change  the  color,  and  extraction  of  the  mixture  with  acetic  ether. 

f. — Quantitative. — The  estimation  of  gallic  acid,  in  solution 
free  from  other  oxidizing  Agents,  may  be  accurately  done  by  ti- 
tration  with  permanganate,  in  presence  of  indigo  solution,  as  in 
Lowenthal's  method  for  tannin  (see  under  Tannin).1  The  gallic 
acid  consumes  more  permanganate  than  an  equal  weight  of  tan- 
nin does,  and  more  than  does  the  quantity  of  tannin  from  which 
-it  could  be  obtained.3  The  permanganate  solution  may  be  stand- 
ardized by  freshly  dissolved  weighed  gallic  acid  of  given  purity. 

1  LOWENTHAL,  1877:  Zeitsch.  an.  Chem.,  16,  39. 

2  PROCTER,  Chem.  News,  36,  60. 


GLYCERIN.  323 

Tannin,  if  present,  must  be  first  removed  as  in  Luwenthal's 
method. — Gallic  acid  may  be  estimated,  in  absence  of  tannin,  by 
the  increase  of  weight  of  zinc  oxide.  A  weighed  quantity  of  the 
oxide,  freshly  ignited,  is  digested  with  the  solution  of  free  gallic 
acid,  filtered  out,  washed,  dried  at  110°-120°C.,  and  its  increase 
of  weight  taken  as  gallic  acid. — A  method,  after  FLECK,  by  pre- 
cipitation as  copper  salt,  giving  approximate  results  in  presence 
of  tannin,  is  conducted  as  follows  :  The  prepared  solution  is  fully 
precipitated  with  a  filtered  solution  of  cupric  acetate ;  the  pre- 
cipitate washed  and  then  exhausted  with  cold  solution  of  car- 
bonate of  ammonium.  The  last  solution,  containing  all  the  gallate 
of  copper  with  a  very  little  tannate,  is  evaporated  to  dryness,  the 
residue  moistened  with  nitric  acid,  ignited,  and  weighed  as  oxide 
of  copper.  This  weight  multiplied  by  0.9  gives  the  quantity  of 
gallic  acid,  the  full  ratio  being  0.9126,  but  allowance  is  made  for 
solution  of  a  little  tannate  by  the  carbonate  of  ammonium.  The 
ratio  between  oxide  of  copper  and  tannic  acid  is  1.304. 

g. — "An  aqueous  solution  of  gallic  acid  should  not  precipi- 
tate alkaloids,  gelatin,  albumen,  gelatinized  starch,  or  solution  of 
tartrate  of  antimony  and  potassium  with  chloride  of  ammonium 
(distinction  from  tannic  acid) "  (U.  S.  Ph.) 

GALLOTANNIN.     See  TANNINS. 

GLYCERIN.  Glycerol.  C3H8O3  =  92.  (C3H5)'"(OH)3.— 
Propenyl,  C3H5  =:  CH2 .  CH .  CH2 ,  is  a  residue  of  propane,  the 
third  member  of  the  marsh-gas  series.  Glycerin  is  produced, 
along  with  candle-manufacture  and  the  production  of  the  fat 
acids  ( "  stearin  "  and  "  olein  " ),  by  saponification  of  the  fats,  with 
water  as  superheated  steam,  or  with  lime,  or  with  sulphuric  acid. 
It  occurs  also  among  the  products  of  the  alcoholic  fermentation 
of  sugar. 

Glycerin  taken  alone  is  recognized  by  its  sensible  properties 
(a) ;  in  dilute  forms  or  in  certain  admixtures  it  is  revealed  by 
the  bead-test  with  borax,  its  power  of  neutralizing  boracic  acid, 
arid  the  odor  of  its  vapors  when  strongly  heated  (d).  As  a  re- 
ducing agent  it  affects  permanganate  promptly  in  alkaline  mix- 
ture, scarcely  at  all  in  neutral  or  acid  liquids,  and  does  not  alter 
Fehling's  solution.  It  is  separated  from  substances  more  vola- 
tile than  water  by  their  distillation,  and  from  non- volatile  sub- 
stances by  its  own  distillation  at  a  heat  a  little  above  that  of  the 
water- bath ;  from  matters  insoluble  in  alcohol,  by  use  of  this  sol- 


324  GLYCERIN. 

vent,  best  by  use  of  lime  and  alcohol  (e).  It  is  estimated  gravi- 
metrically  by  careful  evaporation  with  alcohol -ether  ;  volumetri- 
cally  by  the  permanganate  reaction,  forming  oxalic  acid  (/'). 
Tests  and  authorized  standards  of  purity  (g,  p.  328). 

a. — Glycerin  is  a  colorless,  clear,  syrupy  liquid,  capable  of 
crystallization  in  low  winter  temperatures,  taking  forms  of  the 
rhombic  system,  or  congealing  in  white,  crystalline  masses,  nearly 
or  quite  anhydrous,  the  melting  point  being  22°  C.  Specific 
gravity  at  15°  C.,  taking  water  at  same  temperature  as  standard, 
1.26468  (MENDELEJEFF),  1.2653  (GERLACH);  at  15°  C.,  taking 
•water  at  0°C.,  1.26358  ;  at  17.5°  C.,  1.262  (STROHMER).  Glycerin 
is  very  hygroscopic,  and  at  ordinary  temperatures  it  vaporizes  in 
only  the  slightest  degree,  but  at  100°  C.  it  vaporizes  or  distils  to 
.a  sensible  extent.  At  this  temperature  and  760  millimeters 
barometric  pressure  it  has  a  vapor  tension  of  64  millimeters.  At 
290°  it  boils  with  partial  decomposition,  evolving  vapor  of  acro- 
lein,  C3H4O.  With  superheated  steam  at  180°  to  200°  C.  it  dis- 
tils completely.  Evaporated  in  an  open  dish  at  150°  to  200°  C., 
when  perfectly  pure,  it  leaves  no  residue  behind.  Heated  in  a 
capsule,  at  92°  C.  vapor  rises  almost  imperceptibly,  at  100°  C. 
quite  perceptibly,  at  130°  C.  abundantly,  without  irritating  pro- 
ducts to  a  sensible  extent  at  last-named  temperature  (TRIMBLE, 
1885). 

b. — Glycerin  has  a  pure  sweet  taste  of  much  intensity,  with- 
out odor.  Undiluted  it  has  a  heating  effect  when  applied  to  the 
surface. 

c. — Exposed  to  the  air  glycerin  absorbs  water,  finally  to  the 
extent  of  about  50  per  cent.,  and  is  soluble  in  all  proportions  of 
water  and  of  alcohol.  In  mixture  with  water  the  volume  is  re- 
duced and  the  temperature  raised,  the  greatest  liberation  of  heat 
being  obtained  with  58  parts  of  glycerin  to  42  parts  of  water,  in 
which  proportions  the  contraction  of  volume  is  about  1.1  per 
cent.,  and  the  elevation  of  temperature  about  5°  C.  In  ether, 
glycerin  is  slightly  soluble,  1  part  of  glycerin  of  sp.  gr.  1.23  re- 
quiring 500  parts  of  ordinary  ether  for  solution.  It  is  soluble  in 
a  mixture  of  3  parts  of  alcohol  and  1  part  of  ether ;  also  in  a 
mixture  of  2  volumes  of  absolute  alcohol  and  1  volume  of  com- 
mon ether.  Not  soluble  in  chloroform,  benzene,  or  fixed  oils. 
Soluble  in  a  mixture  of  equal  weights  of  chloroform  and  alcohol. 
Glycerin  when  pure  is  neutral  to  all  indicators.  Glycerin  dis- 
solves the  alkaline  earths  to  a  considerable  extent,  with  chemical 
combination.  If  the  solutions  be  charged  with  carbon  dioxide 
the  earths  are  mainly  precipitated.  With  lead  it  forms  the 


GL  YCERIN.  325 

flyceride,  C3H6PbO3 ,  crystallizable  in  fine  white  needles.     So- 
ium  glyceride,  C3H7NaO3,  is   a   white,  hygroscopic   powder, 
resolved  by  water  into  glycerin  and  sodium  hydroxide. 

d. — "  If  a  fused  bead  of  borax  on  a  loop  of  platinum  wire  be 
moistened  with  glycerin  previously  made  slightly  alkaline  with 
diluted  solution  of  soda,  and  after  a  few  minutes  held  in  a  color- 
less flame,  the  latter  is  tinted  deep  green." — Glycerin  abstracts 
boric  acid  from  borax,  so  as  to  affect  the  reaction  to  litmus.  If  a 
borax  solution  be  colored  (blue)  with  litmus,  and  a  solution  con- 
taining glycerin,  neutral  in  reaction,  be  also  colored  with  blue 
litmus,  on  mixing  the  solutions  a  red  color  will  be  obtained. 
Warming  restores  the  blue  color,  but  the  red  reappears  when  the 
liquid  is  cool  again. — If  a  portion  of  glycerin  be  heated  to  boil- 
ing in  a  dry  test-tube,  the  characteristic  acrid  vapors  of  acrolein 
will  be  obtained.  If  in  aqueous  mixture,  the  glycerin  must  be 
concentrated  for  the  test,  which  is  also  rendered  more  delicate 
by  the  addition  of  a  little  dry  phosphoric  acid  or  potassium  bi- 
sulphate.  Glycerin  alone  is  not  carbonized  by  heating  with 
either  of  these  agents. — If  2  drops  of  glycerin  (free  from  bodies 
carbonized  by  sulphuric  acid)  be  mixed  with  2  drops  each  of 
melted  phenol  and  sulphuric  acid,  and  heated  somewhat  over 
120°  C.  to  the  production  of  a  resinous  mass,  and  when  cold  am- 
monia be  added,  a  fine  carmine-red  color  will  be  obtained. 

Permanganate  solution,  acidulated  with  sulphuric  acid,  is  but 
very  slowly  decolored  by  glycerin,  and  even  by  boiling  heat  the 
oxidation  of  the  glycerin  is  difficult.  But  in  alkaline  solu- 
tion of  the  permanganate  decoloration  by  glycerin  is  prompt, 
the  reaction  being  as  follows  (BENEDIKT  and  ZSIGMONDY)  : 
C3H?O3  +  2K2Mn2O8  —  K2C2O4  +  K2CO3  +  4MnO2  +  4II2O. 
Fehling's  solution  is  but  very  slightly  reduced  by  glycerin.  A 
quite  concentrated  solution  of  pure  glycerin,  boiled  10  minutes 
with  Fehling's  solution,  and  then  set  aside  for  24  to  48  hours, 
yields  some  precipitate  of  the  cuprous  hydroxide.  But  dilution 
of  the  glycerin  with  ten  volumes  of  water  prevents  the  reaction. 

e. — Separations. — Glycerin  in  watery  mixture  is  not  concen- 
trated by  evaporation  without  loss,  neither  is  any  part  of  it  ob- 
tained anhydrous  by  continued  evaporation.  From  100°  to  130° 
C.  glycerin  alone  distils  unchanged  (TKIMBLE,  1885).  From  so- 
lution in  alcohol  it  can  be  recovered  almost  without  loss  in  the 
residue  left  by  gentle  evaporation  with  additions  of  a  little  ab- 
solute alcohol  from  time  to  time. — Glycerin  may  be  separated 
from  fluid  extracts  of  vegetable  drugs,  also  from  wines,  or  from 
sugars  and  gums,  as  follows :  Slaked  lime  is  added,  the  liquid  is 


326  GLYCERIN. 

treated  with  a  little  alcohol  and  evaporated  to  dryness  at  a  very 
gentle  heat,  adding  small  portions  of  alcohol  in  completing  the 
evaporation,  and  then  exhausted  with  several  portions  of  alcohol 
of  about  ninety  per  cent,  strength  by  weight.  Tiie  clear  alcoho- 
lic solution  is  evaporated,  with  the  alcoholic  filter-washings  if 
filtration  has  been  required,  and  the  residue  will  be  approxi- 
mately pure  glycerin.  In  the  case  of  certain  extracts,  and  as  a 
precaution  in  separating  from  unknown  matters,  it  is  desirable 
to  take  up  the  glycerin  residue  with  a  mixture  of  two  volumes  of 
absolute  alcohol  and  one  volume  of  stronger  ether,  filtering  if 
need  be,  and  evaporating  again.  With  quantitative  precautions 
in  completing  the  extractions,  and  washing  filters,  then  evapo- 
rating in  weighed  beakers,  the  operation  will  serve  as  a  good 
practical  estimation,  though  of  course  absolute  glycerin  is  not 
obtained  for  weight.  Instead  of  the  ether-alcohol,  a  mixture 
of  equal  weights  of  chloroform  and  alcohol  does  well  in  some 
cases  as  a  solvent  for  purification,  but  the  former  is  generally  the 
best.  The  lime  is  an  essential  aid  in  holding  sugars,  gums,  and 
many  extractive  matters,  from  solution  in  the  ninety-per-cent. 
alcohol.1  From  soaps  glycerin  is  obtained  by  acidulating  with 
dilute  sulphuric  acid  for  removal  of  the  fat  acids,  addition  of  ba- 
rium carbonate  for  removal  of  excess  of  sulphuric  acid,  when  al- 
cohol is  added,  alkali  sulphates  filtered  out,  and  evaporation  con- 
ducted with  the  addition  of  alcohol  and  filtration. 

f. — Quantitative. — Estimation  of  glycerin  of  fats.  About 
30  grams  of  the  dried  and  filtered  clear  fat,  with  15  grams  potas- 
sium hydroxide  or  21  grams  sodium  hydroxide  dissolved  in  the 
least  sufficient  amount  of  water,  and  50  c.c.  alcohol,  are  digested 

irrhe  use  of  the  lime  with  the  alcohol  was  reported  upon,  for  estimation  of 
the  glycerin  of  wines,  by  E.  REICHARDT,  1875:  Archiv  d.  Phar.,  [3],  7,408: 
Zeitsch.  anal.  CJiem.  (1878),  17,  109.  An  elaborate  examination  of  this  method 
of  separating  glycerin  from  wines  was  made  by  NEUBAUER  and  BORGMAN,  1878: 
Zeitsch.  anal.  Chem.,  17-,  445.  These  authors  found  a  considerable  impurity 
in  the  glycerin  extracted  from  wines  by  Reichardt's  directions,  but  they  were 
able  to  recover  very  nearly  the  quantity  of  glycerin  added  to  wines.  Control 
analyses  by  Reichardt's  method,  in  separation  from  cane  sugar,  grape  sugar, 
and  medicinal  fluid  extracts,  were  made  by  the  author  and  another  (A.  B. 
Prescott  and  0.  H.  Koehnle)  in  1878:  New.  Bern.,  New  York,  7,  354.  From 
mixture  with  sucrose  99.8  per  cent,  of  the  glycerin  taken  was  recovered :  from 
mixture  with  glucose  99.7  per  cent,  was  recovered :  in  both  cases  the  glycerin 
being  obtained  free  from  sugar.  From  fluid  extracts  of  cinchona  and  of  gen- 
tian, to  which  sugars  had  been  added,  there  were  separated  97.6,  98.6,  and 
95.4  per  cent,  of  the  glycerin  added.  The  ether-alcohol  mixture  mentioned  in 
the  text  separated  pure  glycerin  from  sucrose,  but  not  from  glucose,  some  of 
which  was  taken  up  with  the  glycerin.  The  same  was  found  to  be  true  of  the 
chloroform-alcohol  mixture  referred  to  in  the  text. 


GLYCERIN.  327 

over  the  water-bath  to  perfect  saponification.  The  alcohol  is 
evaporated  off,  the  soap  dissolved  in  water,  diluted  sulphuric 
acid  is  added,  and  the  mixture  warmed,  until  the  separation  of 
the  surface-layer  of  fat  acids  is  complete.  When  cold  the  fat 
crust  is  removed,  the  aqueous  liquid  filtered,  and  the  fat  acids 
washed  on  the  filter  ;  or  the  fat  acids  are  filtered  out  as  in  Heh- 
ner's  method  (p.  250).  The  excess  of  sulphuric  acid  in  the  fil- 
trate is  taken  up  with  barium  carbonate,  the  nitrate  evaporated, 
with  additions  of  alcohol,  to  a  thin  syrupy  consistence,  then 
treated  with  a  mixture  of  3  parts  of  95$  alcohol  and  1  part  of 
ether  and  filtered,  washing  the  filter  with  the  same  mixed  sol- 
vent. This  filtrate  is  evaporated  in  a  platinum  dish,  at  100°  C., 
until  two  weighings  do  not  differ  over  3  to  5  milligrams,  or  dried 
in  a  desiccator  to  a  constant  weight.  The  residue  is  then  ignited, 
and  the  weight  of  the  ash  deducted. 

The  glycerin  of  strictly  neutral  fats  can  be  calculated  from 
Kottstorl'er's  number  —  the  milligrams  of  potassium  hydroxide  to 
saponify  1  gram  of  fat.  Taking  these  milligrams  as  thousandths 
of  a  gram,  3KOH  :  C3H8O3  :  :  168  :  92. 

Estimation  by  oxidation  with  p&rmanganate  (BENEDIKT  and 
ZsiGMONDY.1)  The  reaction  is  stated  under  d,  and  the  resulting 
oxalic  acid  is  the  measure  obtained.  The  fat  is  saponified  with 
potash  and  methyl  alcohol,  the  alcohol  evaporated  off,  the  residue 
dissolved  by  hot  water,  the  soap  decomposed  by  diluted  hydro- 
chloric acid,  and  the  fat  acids  melted  and  set  aside  until  fully 
clear.  Some  hard  paraffin  is  added  to  the  fat  acids,  the  mixture 
cooled  and  filtered,  and  the  residue  washed.  The  filtrate  is  neu- 
tralized with  potassa,  and  is  now  ready  for  the  reaction.  -  First 
add  10  grams  potassium  hydroxide,2  and  then  add,  at  ordinary 
temperature,  of  a  permanganate  solution  of  about  5$  strength 
sufficient  to  render  the  liquid  no  longer  green  but  blue  or  black 
in  color.  The  mixture  is  heated  to  "boiling,  with  precipitation 
of  manganese  dioxide,  and  then  enough  sulphurous  acid  is  added 
to  make  the  red  liquid  colorless,  and  the  mixture  filtered  through 
a  wet  filter  large  enough  to  contain  at  least  half  at  once,  and  the 
residue  well  washed  with  boiling  water.  If  the  last  washings  be 
turbid  with  manganese  dioxide,  a  little  acetic  acid  is  added.  The 
liquid  is  now  heated  to  boiling,  and  fully  precipitated  by  calcium 
acetate  or  chloride.  The  oxalate  of  calcium  precipitated  is  esti- 


:  Analyst,  10,  205,  from  Chem.  Zeit.  An  investigation  of  this  and 
other  methods,  now  being  made  by  A.  J.  BAUMHARDT  and  the  author,  will  be 
communicated  at  an  early  date. 

2  Fox  and  WANKLYN  (1886  :     Chem.  News,  53,  15)  take  a  quantity  of  ma- 
terial containing  not  over  0.25  gram  of  glycerin,  and  add  5  grams  of  KOH. 


328  GLYCERIN. 

mated  at  the  discretion  of  the  operator.  But  inasmuch  as  the 
precipitate  is  liable  to  contain,  as  impurities,  calcium  silicate  and 
calcium  sulphate,  it  is  better  to  estimate  the  oxalate  volurnetri- 
cally  with  permanganate,  or,  after  ignition,  by  titration  with  half 
normal  hydrochloric  acid,  using  diraethylanilin  orange  as  an  in- 
dicator. The  hydrochloric  acid  may  be  standardized  by  anhy- 
drous sodium  carbonate.  106  parts  of  Na2CO3,  or  72.8  parts  of 
HC1,  indicate  90  parts  of  H2C2O4,  or  92  parts  of  glycerin. — In 
this  operation  methyl  alcohol  is  used  because  ethyl  alcohol,  if 
employed,  is  not  wholly  expelled,  and  suffers  oxidation  by  per- 
manganate in  alkaline  liquid  with  formation  of  oxalic  acid.  So- 
luble fat  acids  do  not  interfere.  The  method  is  applicable  to 
any  ordinary  neutral  mixture  of  glycerin. — Benedikt  and  Zsig- 
mondy  obtained  the  following  percentages  of  glycerin:  From 
olive  oil,  10.15-10.38;  linseed  oil,  9.45-9.97  ;  tallow,  9.94-9.98- 
10.21;  butter,  11.59;  Japan  wax,  10.3-11.2;  beeswax,  0. 

g. — Tests  of  purity. — The  U.  S.  Ph.  prescribes  as  follows: 
"  Glycerin  should  be  neutral  to  litmus-paper.  Upon  warming  a 
portion  of  5  or  6  grams  with  half  its  weight  of  diluted  sulphu- 
ric acid,  no  butyric  or  other  acidulous  odor  should  be  obtained. 
A  portion  of  2  or  3  grams,  gently  warmed  with  an  equal 
volume  of  sulphuric  acid  in  a  test-tube,  should  not  become  dark- 
colored.  A  portion  of  about  2  grams,  heated  in  a  small  open 
porcelain  or  platinum  capsule,  upon  a  sand  bath,  until  it  boils, 
and  then  ignited,  should  burn  and  vaporize  so  as  to  leave  not 
more  than  a  dark  stain  (absence  of  sugars  and  dextrin,  which 
leave  a  porous  coal).  A  portion  heated  to  about  85°  C.  (185° 
F.)  with  test  solution  of  potassio-cupric  tartrate  should  not  give 
a  decided  yellowish-brown  precipitate,  and  the  same  result  should 
be  obtained  if,  before  applying  this  test,  another  portion  be 
boiled  with  a  little  diluted  hydrochloric  acid  for  half  an  hour 
(absence  of  sugars).  After  full  combustion  no  residue  should  be 
left  (metallic  salts).  Diluted  with  ten  times  its  volume  of  distil- 
led water,  portions  should  give  no  precipitates  or  colors  when 
treated  with  test  solutions  of  nitrate  of  silver,  chloride  of  barium, 
sulphide  of  ammonium,  or  oxalate  of  ammonium  (acrylic,  hy- 
drochloric, sulphuric,  and  oxalic  acids,  iron  and  calcium  salts)." 

"  Shaken  with  an  equal  volume  of  sulphuric  acid,  no  colora- 
tion, or  only  a  very  slight  straw  coloration,  should  result.  When 
gently  heated  with  diluted  .sulphuric  acid,  no  rancid  odor  is 
produced.  Sp.  gr.  about  1.25  "  (Br.  Ph.) 

"Sp.  gr.  1.225  to  1.235.  Heated  in  an  open  dish  to  boil- 
ing, and  then  ignited,  it  should  burn  without  residue.  It  should 


HYDRASTINE.  329 

not  reduce  ammoniacal  solution  of  silver  nitrate,  at  ordinary  tem- 
perature, within  half  an  hour.  Warmed  with  an  equal  volume 
of  sodium  hydrate  solution  (15$),  it  should  not  be  colored,  nor 
should  ammonia  be  developed  ;  and  gently  warmed  with  diluted 
sulphuric  acid,  no  disagreeable  rancid  odor  should  be  given  " 
(Ph.  Germ.) 

Sp.  gr.  1.242.  Undergoes  complete  combustion,  leaving  no 
residue  (Ph.  Fran.)  Impurities :  lead  salt,  lime,  lime  sulphate, 
sodium  chloride,  oxalic  acid,  butyric  acid.  Adulterations  :  ex- 
cess of  water,  dextrin,  glucose  syrup,  honey  (Ph.  Fran.) 

The  sulphuric  acid  test  is  doubtless  severe  enough  if  the 
directions  of  the  U.  S.  Ph.  be  followed  with  omission  of  the 
gentle  warming,  as  sufficient  elevation  of  temperature  results 
from  the  admixture.  The  silver  nitrate  test  is  much  influenced 
by  the  conditions  of  time  and  light.  If  treatment  with  test 
solution  of  silver  nitrate  for  half  an  hour,  in  the  dark,  be  adopt- 
ed, the  test  is  certainly  not  too  severe.  The  combustion  test  is 
efficient  for  the  exclusion  of  carbohydrates. 

Messrs.  Patch,  Warder,  and  Goebel  have  each  lately  reported 
upon  the  quality  of  glycerin  sold  in  the  United  States.1 

GUARANINE.     See  CAFFEINE,  p.  77. 
HOMATROPINE.     See  MIDKIATIC  ALKALOIDS. 
HOMOQUININE.     See  CINCHONA  ALKALOIDS,  p.  92. 

HYDRASTINE.  C22H23NO6  =  397  (MAHLA,  1863).— The 
colorless  alkaloid  of  Hydrastis  Canadensis,  or  "  golden  seal "  root, 
in  which  it  accompanies  the  yellow  alkaloid  berberine.  Hydras- 
tine  is  also  a  commercial  name  for  medicinal  preparations  of  the 
yellow  alkaloid  berberine,  from  Hydrastis.2  Perrins  obtained 

1  Proc.  Am.  Pharm.  for  1885:  33,  pp.  481,  484,  485. 

2  The  colorless  alkaloid  of  Hydrastis  was  announced  as  a  crystallizable  al- 
kaloidal  body,  in  1851,  by  DURAND,  of  Philadelphia,  who  proposed  the  name 
"hydrastine,"  but  was  left  in  doubt  because  unable  to  obtain  crystallizable 
salts.      The  name  "hydrastine  "  had  been  given  to  the   yellow  alkaloid   of 
golden  seal  by  RAFINESQUE  in  his  "Medical  Flora  of  the  United  States,"   vol. 
i.,  1828.     In  Europe  the  yellow  alkaloid  had  been  found  in  other  plants  and 
named   "  jamaicine  "*by  HUTTENSCHMID  in   1824,  "  xanthopicrite  "  by  CHE- 
VALLIER  and  PELLETAN 'in  1826,  and  '•  berberine  "  by  BUCHNER  and  HERBERGER 
in  1830,  with  a  better  description  by  FLEITMAN  in  1847.     The  yellow  alkaloid 
was  found  in  Hydrastis  by  DURAND  in  1851,  and  identified  with  the  yellow  al- 
kaloid of  Berberis  and  other  plants  by  MAHLA  as  late  as  1862,  and  by'PERRiNS, 
1863.     Prof.  LLOYD  states  (1884)  that  "  there  is  little  indication  that  the  term 
hydrastine,"  as  applied  to  the  yellow  alkaloid   of  Hydrastis,   "  will  be  sup- 


330  HYDRASTINE. 

\\  per  cent,  from  the  dried  root.  Lloyd  states  the  yield  in  manu- 
facture to  be  J  to  }  per  cent. 

Hydrastine  is  characterized  by  its  crystalline  form  when  free, 
and  the  amorphous  condition  of  its  salts  (&),  with  the  reactions  it 
gives  as  an  alkaloid  (d).  It  is  prepared  from  golden  seal  as  di- 
rected (tf),  and  estimated  gravimetrically  (/"). 

a. — Hydrastine  forms  four-sided  prisms,  orthorhombic,  lus- 
trous when  perfect,  usually  broken  and  opaque  white.  The  crys- 
tals melt  at  135°  C.  (MAHLA),  at  1 32°  C.  (POWEK),  and  in  strong 
heat  decompose  with  odor  of  phenol. — The  salts  of  hydras- 
tine  refuse  to  crystallize.  The  hydrochloride  is  anhydrous, 
C22H23]SrO6.HCl;  also  the  sulphate,  (C22H23NO6)2H2SO4.- 
Hydrastine  is  levo-rotatory,  with  a  specific  rotatory  power,  in 
chloroformic  solution,  of  [a]  D=  —170°  (POWER). 

b. — Hydrastine,  free,  is  tasteless  and  odorless.  The  salts 
have  an  acrid  taste.  Hydrastine  is  the  true  active  principle  of 
Hydrastis  Canadensis  (Prof.  BARTHOLOW,  1885  ').  Three  grains 
of  the  hydrochlorate  caused  the  death  of  a  frog  in  four  minutes, 
and  the  results  upon  rabbits  were  corresponding.  Like  strych- 
nine, it  causes  death  by  arrest  of  the  respiratory  movements  in  a 
tonic  spasm. 

c. — Hydrastine  is  not  appreciably  soluble  in  water  or  in  di- 
lute alkaline  solutions.  At  15°  C.  it  dissolves  in  1.75  parts  of 
chloroform,  in  15.7  parts  of  benzene,  in  83,46  parts  of  ether, 

planted  by  berberine  at  any  immediate  day":  "Drugs  and  Medicines  of  North 
America,"  vol.  i.  100. 

A.  B.  DURAND,  1851:  Am.  Jour.  Phar.,  23,  112.  W.  S.  MERRELL,  1862: 
Am.  Jour.  Phar.,  34,  July.  J.  D.  PERKINS,  1802:  Phar.  Jour.  Trans.,  [2],  3, 
546  (May):  first  separation  as  a  colorless  alkaloid.  F.  MAHLA,  1886:  Am. 
Jour.  Sci.,  [2],  36,  27.  J.  U.  LLOYD,  1878:  Proc.  Am.  Pharm.,  26,  805.  F. 
B.  POWER,  1884:  Proc.  Am.  Pharm.,  32,  448.  J.  U.LLOYD,  a  full  history: 
"Drugs  and  Medicines  of  North  America,"  1884,  vol.  i.  130.  FREUND  and 
WILL,  a  critical  investigation,  1886:  Ber.  d.  chem.  (res.,  19,  2797;  Phar.  Jour. 
Trans.,  16. 

Upon  a  second  colorless  alkaloid  in  Hydrastis  see  A.  K.  HALE,  Ann  Ar- 
bor, 1873:  Am.  Jour.  Phar.,  45,  247  J.  C.  BURT,  1875:  Am.  Jour.  Phar  ,  47, 
481.  H.  LERCHEN,  Philadelphia,  1878:  Am.  Jour.  Phar.,  50,  470.  J.  U. 
LLOYD,  1884:  "  Drugs  and  Med.  of  North  America,"  vol.  i.  139.  According 
to  FREUND  and  WILL  (1886,  loc.  cit.)  hydrastine  has  decided  chemical  resem- 
blance to  narcotine  (CasHssNOv).  When  oxidized  by  permanganate  or  by  di- 
lute nitric  acid,  hydrastine  was  found  to  yield  a  crystalline  acid  identical  with 
opianic  acid,  together  with  a  crystalline  base  closely  resembling  cotarnine 
(compare  under  Narcotine,  d). 

1  Communication,  from  physiological  trials,  in  "Drugs  and  Medicines  of 
North  America,"  i,  156. 


HYDRASTINE.  331 

and  in  120  parts  of  alcohol  (  POWER,  1884 ').  It  does  not  dissolve 
in  petroleum  benzin. — The  ordinary  salts  are  soluble  in  water ; 
the  tannate  and  picrate  insoluble.  The  salts  of  hydrastine  mostly 
have  an  acid  reaction.  The  acetate,  formed  in  solution,  decom- 
poses on  evaporation. 

d. — Alkali  hydrates  precipitate  hydrastine,  from  the  aque- 
ous solution  of  its  salts,  in  a  bulky  amorphous  mass,  which  finally 
takes  on  crystallization,  with  great  reduction  of  volume.  The 
precipitate  is  but  slightly  soluble  in  excess  of  alkalies. — White 
precipitates  are  produced  by  potassium  iodide,  potassium  fer- 
rocyanide,  sulphocyanide,  mercuric  chloride,  and  by  tannic 
acid  (POWER).  The  general  reagents  for  alkaloids  cause  preci- 
pitates— iodine  in  potassium  iodide,  brown ;  Mayer's  solution, 
white ;  platinic  chloride,  orange-yellow  ;  gold  chloride,  yellowish- 
red  ;  picric  acid,  yellow.  Potassium  bichromate  gives  a  yel- 
low precipitate. — Sulphuric  acid,  undiluted,  causes  a  yellow 
color,  becoming  red  on  warming,  and  turning  to  brown  on 
adding  a  crystal  of  bichromate.  Concentrated  sulphuric  acid 
and  molybdate  of  ammonium  give  an  olive-green  color  (POWER). 
Concentrated  nitric  acid  produces  only  a  yellowish  color  in  the 
cold.  The  hydrochloride  solution,  treated  with  chlorine,  shows 
blue  fluorescence  (MAHLA).  Ethyl-hydrastine  was  obtained  in 
hydriodide  by  PowER,2  who  also  formed  a  hydro-hydrastine 
C22Ho7NO6,  in  the  hydrochloride. 

e. — Hydrastine  may  be  separated  from  golden  seal  root  as  fol- 
lows (POWER,  LLOYD  :  1884) :  The  powdered  root  is  moistened 
with  alcohol  and  percolated  with  the  same  solvent ;  sulphuric 
acid  in  strong  excess  is  added  to  the  percolate ;  after  four  hours 
the  crystals  of  berberine  sulphate  are  filtered  out ;  ammonia  is 
added  to  the  filtrate  until  it  has  but  a  slightly  acid  reaction  and 
the  crystallized  ammonium  sulphate  is  filtered  out ;  the  filtrate 
is  concentrated  (by  distillation)  to  a  syrupy  consistence,  and  the 
residue  poured  into  ten  times  its  volume  of  cold  water.  After 
twenty  four  hours  the  precipitated  resinous  substances,  oils,  etc., 
are  filtered  out ;  ammonia- water  in  decided  excess  is  added  to 
the  filtrate ;  and  the  resulting  precipitate,  impure  hydrastine, 
collected  and  dried.  The  product  is  digested  with  100  times  its 
weight  of  cold  water,  to  which  sulphuric  acid  has  been  carefully 
added  to  slight  acid  reaction  ;  after  twenty-four  hours  the  liquid 
is  filtered  and  ammonia  in  excess  added  to  the  filtrate,  the  pre- 
cipitate collected  on  a  strainer,  dried,  and  then  powdered  and 

1  Proc.  Am.  Pharm.,  32,  450.        21884:  Proc.  Am.  Pharm.,  32,  454. 


332  HYDRASTINE. 

extracted  with  boiling  alcohol.  On  cooling  the  solution  gives 
crystals  of  hydrastine,  still  dark  yellow  with  impurities,  and  to 
be  recrystallized  from  alcohol,  repeatedly,  until  perfectly  color- 
less. 

fm — Quantitative — The  free  alkaloid  crystallizes  anhydrous, 
C22H23NO6,  and  the  crystals  or  the  well- washed  precipitate  by 
ammonia,  when  obtained  colorless,  may  be  dried  at  100°  C.  for 
weight.  The  gold  chloride  of  hydrastine,  by  precipitation  of 
the  hydrochloride  of  the  alkaloid  with  auric  chloride,  and  drying 
at  100°  C.,  gave  Prof.  Power  J  16.92  per  cent,  of  metallic  gold. 
The  formula,  (C22H23\N~O6 .  HCl)2Au013  =  1 1 69.2,  indicates  16.78 
per  cent,  of  gold  and  67.91  per  cent,  of  hydrastine. 

The  platinum  chloride,  obtained  by  precipitation  of  the  hy- 
drochloride solution,  gave  MAHLA  16.17$  of  platinum ;  the  for- 
mula (C22[-l23NO6.HCl)2PtCl4  indicating  16.120  of  platinum. 

HYDROQUININE.     See  CINCHONA  ALKALOIDS,  p.  91. 

HYGRINE.     See  COCA  ALKALOIDS,  p.  173. 

HYOSCYAMINE.     See  MIDRIATIC  ALKALOIDS. 

IGASURINE.     See  STRYCHNOS  ALKALOIDS. 

INKS.     See  TANNINS. 

JAPACONITINE.     See  ACONITE  ALKALOIDS,  p.  18. 

KATRINES.     See  CINCHONA  ALKALOIDS,  p.  166. 

LANTHOPINE.     See  OPIUM  ALKALOIDS. 

LARD.     See  FATS  and  OILS,  p.  290. 

LINOLEIC  ACID.     See  p.  249. 

LINSEED  OIL.     See  p.  284. 

MADDER  RED.     See  COLORING  MATTERS,  p.  189. 

MAGENTA.     See  p.  191. 

1 1884:  Proc.  Am.  Pharm.,  32,  453. 


MALIC  ACID.  333 

MALIC  ACID.  H8C4H405  =  110.  C.O2H .  CH2 .  CHOH . 
OO2H.  Aepfelsaure. — Distributed  widely  through  the  vegetable 
kingdom.  Reported  already  in  not  less  than  200  plants  (Huse- 
mann's  u  Pflanzenstoffe  ").  Most  abundant  in  fruits,  but  found 
in  other  parts  of  plants.1  Usually  obtained  from  mountain-ash 
berries  or  from  unripe  apples.  LENSSEN  (1870)  obtained  6.62$ 
from  barberry  berries,  only  1.58$  from  mountain-ash  berries. 
Others  report  about  2$  from  the  latter.  It  is  abundant  in  to- 
bacco. It  is  believed  identical  with  Minispermic  acid,  Solanic 
acid,  Tannacetic  acid,  Euphorbic  acid,  and  perhaps  with  Igasuric 
acid.  It  is  formed  artificially  from  asparagin,  from  tartaric 
acid,  and  from  succinic  acid.  It  is  not  manufactured  for  use. 

Malic  acid  is  identified,  more  especially,  by  its  sublimation 
products  (0),  the  deportment  of  its  lead  precipitate  when  warmed 
and  when  treated  with  ammonia,  and  the  formation  of  its  cal- 
cium precipitate  by  alcohol,  also  by  its  reduction  of  dichromate 
with  apple-odor  (d).  It  is  separated  from  citric,  tartaric,  and 
oxalic  acids  by  non -precipitation  in  boiling  calcic  aqueous  solu- 
tions, or  by  the  alcohol  solubility  of  its  ammonium  salt  (e) ;  from 
fruit  juices  by  systematic  treatment  (e).  Estimated,  gravimet- 
rically,  as  lead  salt  (/"),  or  as  calcium  salt  weighed  as  sulphate. 
Methods  of  preparation  are  indicated  at  g. 

a. — Malic  acid  crystallizes  with  some  difficulty,  and  from 
syrupy  solution,  in  tufted  needles  or  in  four  or  six  sided  prisms, 
anhydrous,  and  deliquescent  in  the  air. — Heated  in  a  small  retort 
over  an  oil-bath  or  sand-bath  to  175°  or  180°  C.,  malic  acid 
evolves  vapors  of  maleic  and  fumaric  acids,  which  crystallize  in 
the  retort  and  receiver.  The  fumaric  acid  forms  slowly  at  150°  C., 
and  mostly  crystallizes  in  the  retort  in  broad,  colorless  rhombic 
or  hexagonal  prisms,  which  vaporize  without  melting  at  about 
200°  C.,  to  condense  in  needles,  and  are  soluble  in  250  parts  of 
water,  easily  soluble  in  alcohol  or  ether.  If  the  temperature  is 
suddenly  raised  to  200°  C.  the  maleic  acid  is  the  chief  product. 
Maleic  acid  crystallizes  in  oblique,  rhomboidal  prisms,  which 
melt  at  130°  C.  and  vaporize  at  about  160°  C.,  condensing  in 
hard  needles,  and  are  readily  soluble  in  water,  alcohol,  and  ether. 
The  test  for  malic  acid,  by  heating  to  175°  or  180°  C.,  may  be 
made  in  a  test-tube,  with  a  sand-bath,  the  sublimate  of  fumaric 
and  maleic  acids  condensing  in  the  upper  part  of  the  tube.  Malic 
acid  melts  below  100°  C.,  and  does  not  lose  weight  at  120°  C.  ;  at 

1  For  list  of  plants  containing  malic  acid  see  Grinelin-Kraut's  "  Handbuch," 
v.  336,  Supplem.  884. 


334  MALIC  ACID. 

the  temperature  of  the  test  water-vapor  is  separated — maleic  and 
f  umaric  acids  both  having  the  ultimate  composition  of  malic  an- 
hydride (C4H4O4). — Solution  of  malic  acid  quickly  moulds,  with 
various  products.  Fermented  with  yeast  or  cheese,  in  presence 
of  calcium  carbonate,  succinic  acid  is  formed,  with  acids  of  the 
formic  series. 

b,  c. — Malic  acid  is  freely  soluble  in  water,  alcohol,  and  ether  ; 
the  malates  soluble  or  sparingly  soluble  in  water,  mostly  insolu- 
ble in  alcohol ;  ammonium  malate  soluble  in  alcohol. — Malic 
acid  is  dibasic,  and  forms  normal  and  acid  salts.  Like  tartaric 
and  citric  acids,  it  prevents  the  precipitation  of  metals  by  alkalies. 

d. — Solution  of  acetate  of  lead  precipitates  malic  acid,  more 
perfectly  after  neutralizing  with  ammonia,  as  a  white  and  fre- 
quently crystalline  precipitate,  which  upon  a  little  boiling  melts 
to  a  transparent,  waxy  semi-liquid  (a  characteristic  reaction,  ob- 
scured by  presence  of  other  salts).  The  precipitate  is  very 
sparingly  soluble  in  cold  water,  somewhat  soluble  in  hot  water 
(distinction  from  Citrate,  Tartrate,  and  Oxalate),  crystallizing 
out  when  cold ;  soluble  in  strong  ammonia,  but  not  readily  dis- 
solved in  slight  excess  of  ammonia  (distinction  from  citrate  and 
tartrate) ;  slightly  soluble  in  acetic  acid  and  in  malic  acid.  If 
the  precipitate  of  malate  of  lead  is  treated  with  excess  of  am- 
monia, dried  on  the  water-bath,  triturated  and  moistened  with 
alcoholic  ammonia,  and  then  treated  with  absolute  alcohol,  only 
the  malate  of  ammonium  dissolves  (distinction  from  Tartaric, 
Citric,  Oxalic,  and  many  other  organic  acids,  the  normal  ammo- 
nium salts  of  which  are  insoluble  in  absolute  alcohol).  Also, 
malic  acid  maybe  separated  from  tartaric,  oxalic,  and  citric  acids, 
in  solution,  by  adding  ammonia  in  slight  excess,  and  then  8  or  9 
volumes  of  alcohol,  which  leaves  only  the  malate  of  ammonium 
in  solution. 

Solution  of  chloride  of  calcium  does  not  precipitate  malic 
acid  or  malates  in  the  cold  (distinction  from  Oxalic  and  Tartaric 
acids)  ;  only  in  neutral  and  very  concentrated  solutions  is  a  pre- 
cipitate formed  on  boiling  (while  calcic  citrate  is  precipitated  in 
neutral  boiling  solutions,  if  not  very  dilute).  The  addition  of 
alcohol,  after  chloride  of  calcium  and  boiling,  in  neutral  solu- 
tion, produces  a  white,  bulky  precipitate  of  calcic  malate  in  even 
dilute  neutral  solutions  (indicative  in  absence  of  sulphuric  and 
other  acids  whose  calcium  salts  are  less  soluble  in  alcohol  than  in 
water).  The  precipitate  dissolves  in  water,  and  is  reproduced  by 
alcohol. 

Solution  of  mercurous  nitrate  gives  a  white,  flocculent  pre- 


MALIC  ACID.  335 

cipitate,  slightly  soluble  in  water  (formed  in  solutions  not  very 
dilute),  not  soluble  in  malic  acid,  but  dissolving  in  dilute  acetic 
acid,  in  sodium  malate  solution,  and  in  excess  of  the  precipitant. 
Silver  malate  precipitate  darkens  but  slightly  on  boiling. — 
Permanganate  of  potassium  is  reduced  but  very  slowly  (distinc- 
tion from  Tartaric  acid) ;  somewhat  more  on  addition  of  sulphuric 
acid. — Nitric  acid,  on  boiling,  is  readily  deoxidized  by  malic  acid, 
brown  vapor  appearing. — Dichromate  of  potassium  solution  is 
reduced,  even  in  the  cold.  By  addition  of  dilute  sulphuric  acid, 
and  warming,  apple  odor  is  developed,  according  to  PAPASOGLI 
and  PoLi,1  who  distinguish  between  malic,  citric,  and  succinic 
acids,  with  use  of  this  reaction,  as  follows :  The  acid,  if  neces- 
sary, may  be  first  precipitated  with  calcium  chloride  and  alcohol ; 
the  precipitate,  freed  from  alcohol,  treated  with  dilute  sulphuric 
acid  and  the  calcium  sulphate  precipitate  filtered  out.  The  fil- 
trate, containing  sulphuric  acid,  is  boiled  with  a  little  dichro- 
mate.  If  (1)  the  liquid  remains  perfectly  yellow,  succinic  acid 
may  be  present ;  (2)  the  color  becomes  yellowish-green,  citric 
acid  may  be  present,  as  well  as  succinic  ;  (3)  if  a  green  color  ap- 
pears, with  odor  of  ripe  or  over-ripe  apples,  malic  acid  is  indi- 
cated. [A  green  color  without  apple  odor  would  result  from 
Tartaric  acid  and  from  numerous  reducing  agents  which  might 
be  precipitated  by  calcium  chloride  with  alcohol.] — In  the  various 
oxidations  of  malic  acid  above  mentioned,  its  products  are  formic 
acid,  carbon  dioxide  and  water,  and,  from  nitric  acid  especially, 
oxalic  acid.  Dichromate  in  the  cold  concentrated  solution  pro- 
duces some  Malonic  acid  (Dessaignes,  1858),  C3H4O4,  crystalliz- 
able,  soluble  in  alcohol  and  ether. — Malic  acid  is  capable  of 
reduction  to  succinic  acid,  by  hydriodic  acid,  at  130°  C.,  and  by 
other  agents. 

e. — Malic  acid  can  be  separated  from  Citric,  Tartaric,  and 
Oxalic  acids  by  the  solubility  of  its  ammonium  salt  in  alcohol,  as 
follows:3  Ammonia  is  added  to  neutral  reaction,  the  solution 
well  concentrated,  and  again  neutralized,  treated  with  7"  or  8 
volumes  of  98$  alcohol,  and  set  aside  12  to  24  hours,  when  it 
may  be  filtered,  and  the  filtrate  treated  with  lead  acetate,  for 
malate.  The  residue  may  contain  ammonium  citrate,  tartrate, 
oxalate. 

The  separation  of  the  same  four  acids  may  be  done,  through 

1 1877:  Oazzettachim.  ital,  7,  294;  Jour.  Chem.  Soc.,  32,  807;  Jahr.  Phar., 
1878,  128. 

2BARFOED,  1868:  Zeitsch.  anal.  Chemie,  7,408.  In  a  full  report  upon  the 
separations  of  malic  acid,  loc.  cit.,  p.  403. 


336       ;  MALIC  ACID. 

the  calcium  precipitates,  with  approximate  closeness,  by  the  fol- 
lowing method  : l 

Solution  of  Oxalic,  Tartaric,  Citric,  and  Malic  acids. 

(If  sulphates  are  present,  remove  by  just  enough  barium 
chloride  with  hydrochloric  acid.)  Add  ammonium  hy- 
drate to  a  slight  alkaline  reaction ;  add  ammonium  chlo- 
ride solution ;  then  enough  calcium  chloride  solution,  and 
let  stand  from  ten  to  twenty  minutes.  Filter. 

Precipitate  (a) :  Oxalate  (complete),  Tartrate  (nearly  complete). 
(If  Phosphates  are  present,  separate  from  oxalate  by  acetic 
acid,  and  identify  by  molybdate.) 

Filtrate  (b) :  Citrate,  Malate. 

Wash  Precipitate  (#),  digest  it  in  the  cold  with  sodium 
.  hydrate   solution  (or  potassium   hydrate   solution),   then 
dilute  a  little  and  filter. 

Residue  (c) :  Oxalate.     Nearly  insoluble  in  acetic  acid. 

Solution  (d) :  Tartrate.  Boil  some  time.  A  precipitate  indi- 
cates tartrate.  Test  by  reducing  power,  with  dichromate, 
silver  salt,  or  permanganate,  and  by  Fenton's  color  test. 

To  Filtrate  (b) — which  must  have  excess  of  calcium 
chloride — add  3  times  its  measure  of  alcohol.  If  a  pre- 
cipitate occurs,  filter. 

Precipitate  (e) :  Citrate,  Malate  (nearly  complete). 

Filtrate  (/):  (May  contain  benzoic,  acetic,  formic  acids,  etc.) 
Wash  Precipitate  (e)  with  alcohol ;  dissolve  on  the  filter 
with  dilute  hydrochloric  acid.  To  the  filtrate  add  ammo- 
nium hydrate  to  slight  alkaline  reaction,  and  boil  for  some 
time.  If  a  precipitate  occurs  filter,  hot  (Filtrate  A). 

Precipitate  (g) :  Citrate.  Confirm  by  dissolving  again  with  hy- 
drochloric acid,  neutralizing  with  ammonia,  and  boiling, 
to  obtain  a  precipitate.  Other  tests  may  be  applied. 

Filtrate  (A) :  Malate.  (May  contain  succinate.)  Try  for  malic 
acid  by  precipitating  with  strong  alcohol.  Test  a  precipi- 
tate, so  obtained,  by  reduction  of  dichromate,  by  lead  pre- 
cipitate, and  other  tests.  To  separate  from  succinic  add 
strong  nitric  acid  and  evaporate  to  dryness,  when  there 
will  be  oxalic  acid  instead  of  malic,  the  succinic  acid  un- 
changed. Test  for  oxalic  by  calcium  salt. 

Malic  acid  may  be  separated  from  Tannic  acid  by  digesting 
the  solution  a  half -hour  with  well- washed  rasped  hide,  and  filter- 
ing out  the  tannate.  The  filtrate  may  be  concentrated  and  treat- 

1  Except  final  tests,  arranged  from  Fresenius'  "Qualitative  Analysis," 
S.  W.  Johnson's  edition  of  1875,  p.  304. 


MECONIC  ACID.  337 

ed  with  lead  acetate,  to  be  tested  for  malic  acid.  Or  both  acids 
may  be  precipitated  by  chloride  of  calcium,  with  a  slight  excess 
of  ammonk  and  alcohol,  and  the  inalate  then  washed  out  of  the 
precipitate  with  water.1  Also,  tannic  and  gallic  acid  may  be  re- 
moved by  acetic  ether. 

For  determining  the  presence  of  malic  acid  in  Fruit  Juices, 
the  expressed  juice  or  water  extract  is  first  precipitated  by  lead 
acetate  solution,  when  the  washed  precipitate  may  be  treated  as 
directed  under  d,  p.  334. 

f. — The  estimation  of  malic  acid  is  usually  done  gravimetri- 
caliy,  as  a  lead  salt.  The  alcoholic  solution  of  malate  of  ammo- 
nium may  be  precipitated  with  acetate  of  lead,  washed  with 
alcohol,  dried  on  the  water-bath,  and  weighed  as  malate  of  lead. 
PbC4H4O5  :  H2C4H4O5::  1  :  0.3953.  The  crystals  of  this  salt 
contain,  three  molecules  of  water  of  crystallization. — The  calcium 
normal  malate  precipitate,  in  strong  alcohol,  may  be  washed  with 
alcohol,  converted  into  sulphate,  this  washed  with  alcohol,  dried, 
ignited,  and  weighed.  CaSO4  :  H2C4H4O5. 

g. — In  the  preparation  of  malic  acid  on  the  small  scale,  the 
lead  precipitate  may  be  decomposed  by  boiling  with  excess  of 
very  dilute  sulphuric  acid ;  filtering,  neutralizing  one- half  the 
filtrate  with  ammonia,  and  mixing  this  with  the  other  half  of  the 
filtrate,  then  evaporating  to  crystallize,  as  ammonium  acid  malate, 
NH4HC4H4O5,  in  large  orthorhombic  prisms.1 

MARGARIC  ACID.     See  FATS  AND  OILS,  p.  244. 

MECONIC  ACID.— H3C7HO7==  200.  Oxychelidonic  acid. 
— Found  only  in  opium,  which  yields  3  to  4$  of  it.  Not  manu- 
factured for  use. — Identified  by  its  physical  properties,  its  pro- 
ducts when  heated,  its  precipitation  by  hydrochloric  acid,  and 
reactions  with  iron  and  other  metals.  It  is  separated  from  opium 
through  formation  of  the  calcium  salt  or  lead  salt. 

Meconic  acid  crystallizes  in  white,  shining  scales  or  small 
rhombic  prisms,  containing  three  molecules  of  crystallization 
water,  fully  given  off  at  100°  C.  At  120°  C.  (248°  F.)  dry 
meconic  acid  is  resolved  into  comenic  acid  /  at  above  200°  C. 

1  Further  for  these  separations,  and  for  separation  from  Gallic,  Benzoic, 
and  other  acids,  see  BARFOED  where  last  cited.     Separation  from  Gallic  acid  is 
directed  by  adding  calcium  chloride  to  the  slightly  alkaline  solution,  and  leav- 
ing some  time,  without  heat,  for  precipitation  of  calcium  gallate. 

2  For  methods  of  preparation  on  larger  scale,  with  first  precipitation  as 
lead  salt,  see  "  Watts's  Dictionary,"  iii.  7*9;  with  first  precipitation  as  calcium, 
salt,  Husemann's  "Pflanzenstoft'e,"  537. 


338  MECONIC  ACID. 


the  comenic  acid  is  resolved  into  pyrocomenic  acid  and  other 
products.  The  sublimate  of  comenic  acid  dissolves  sparingly  in 
hot  water,  not  at  all  in  absolute  alcohol.  It  crystallizes  in  prisms, 
plates,  or  granules.  Solution  of  comenic  acid  gives  a  red  color 
with  ferric  chloride,  green  pyramidal  crystals  with  cupric  sul- 
phate in  concentrated  solution,  and  a  yellowish  white  granular 
precipitate  with  acetate  of  lead.  Meconic  acid  is  soluble  in  115 
parts  of  water  at  ordinary  temperatures,  less  soluble  in  water 
acidulated  with  hydrochloric  acid,  much  more  soluble  in  hot 
water,  freely  soluble  in  alcohol,  slightly  soluble  in  ether.  It  has 
an  acid  and  astringent  taste  and  a  marked  acid  reaction.  Its  salts, 
having  two  atoms  of  its  hydrogen  displaced  by  bases,  are  neutral 
to  test-paper.  Except  those  of  the  alkali  metals,  the  dimetallic 
and  trimetallic  meconates  are  mostly  insoluble  in  water.  Meco- 
nates  are  nearly  all  insoluble  in  alcohol.  They  are  but  slightly 
or  not  at  all  decomposed  by  acetic  acid. 

Solutions  of  meconates  are  precipitated  by  hydrochloric  acid, 
as  explained  above. 

Solution  of  meconic  acid  is  colored  red  by  solution  of  ferric 
chloride.  One  ten-thousandth  of  a  grain  of  the  acid  in  one 
grain  of  water  with  a  drop  of  the  reagent  acquires  a  distinct 
purplish-red  color  ("WORMLEY).  The  color  is  not  readily  dis- 
charged by  addition  of  dilute  hydrochloric  acid  (distinction  from 
Acetic  acid),  or  by  solution  of  mercuric  chloride  (distinction 
from  sulphocyanic  acid). — Solution  of  acetate  of  lead  precipi- 
tates meconic  acid  or  meconates  as  the  yellowish- white  meconate 
of  lead,  Pb3(C7HO7)2,  insoluble  in  water  or  acetic  acld.^ — Excess 
of  baryta  water  precipitates  a  yellow  trimetallic  meconate. — So- 
lution of  nitrate  of  silver  in  excess  precipitates  free  meconic 
acid  on  boiling,  and  precipitates  meconates  directly,  as  yellow 
trimetallic  meconate ;  if  free  meconic  acid  is  in  excess,  the  preci- 
pitate is  first  the  white  dimetallic  meconate :  both  meconates 
being  soluble  in  ammonia  and  insoluble  in  acetic  acid. — Solution 
of  chloride  of  calcium  precipitates  from  solutions  of  meconic 
acid,  and  even  from  neutral  meconates,  chiefly  the  white  mono- 
metallic meconate,  CaH4(C7HO7)2.2H3O,  sparingly  soluble  in 
cold  water.  In  the  presence  of  free  ammonia,  the  less  soluble, 
yellow,  dimetallic  salt,  CaHC7HO7.H2O,  is  formed.  Both  pre- 
cipitates are  soluble  in  about  20  parts  of  water  acidulated  with 
hydrochloric  acid. 

The  separation  of  meconic  acid  from  opium  is  effected  with 
least  loss  by  precipitating  the  infusion  with  acetate  of  lead  (leav- 
ing the  alkaloids  as  acetates  with  some  excess  of  lead  in  the  fil- 
trate). The  precipitate  is  decomposed,  in  water,  with  hydro 


MIDRIA  TIC  ALKALOIDS.  339 

sulphuric  acid  gas,  and  the  filtrate  therefrom  is  concentrated  (and 
acidulated  with  hydiochloric  acid)  to  crystallize  themeconic  acid. 
The  crystals  are  purified  by  dissolving  in  hot  water  and  crystal- 
lizing in  the  cold  after  acidulation  with  hydrochloric  acid. 

The  calcium  rneconate,  precipitated  in  concentrated  solution 
by  Gregory's  process  for  preparation  of  morphia,  as  by  the  Br, 
Pharmacopoeial  preparation  of  morphias  hydrochloras,  is  washed 
with  cold  water  and  pressed.  One  part  of  the  precipitate  is  dib 
solved  by  digestion  in  20  parts  of  nearly  boiling  water  with  3  parts 
of  commercial  hydrochloric  acid,  and'  set  aside  to  crystallize  the 
acid  meconate  of  calcium.  The  crystals  are  purified  from  color 
and  freed  from  calcium  by  repeated  solution  in  the  same  sol  vent, 
used  just  below  100°  C.,  and  each  time  in  a  slightly  diminished 
quantity.  The  acid  may  be  further  decolorized  by  neutralizing 
with  potassic  carbonate,  dissolving  in  the  least  sufficient  quantity 
of  hot  water,  draining  the  magma  of  salt  when  cold,  dissolving 
again  in  hot  water,  and  adding  hydrochloric  acid  to  crystallize. 

MIDRIATIC  ALKALOIDS  OF  THE  SoLANACE*;.1—  The 
Natural  Tropeines.  The  researches  of  LADENBURG  and  others 
(1879-1  88i)  place  the  group  of  alkaloids  distinguished  by  active 
dilatation  of  the  pupil  of  the  eye  as  isomers  of  ^the  common  for- 
mula, C17H23NOo.  These  isomers  are  compounds  of  isorneric 
tropines,  C8liltiNO,  each  in  combination  with  the  same  tropic 
acid,  C9H10Oo  (KRAUT,  1863).  The  union  of  the  basal  tropines 
with  tropic  acid  is  shown  as  follows  : 

C8H1BNO  -|-  C9Hio03  =  C17H23N03  +  H2O. 

This  synthesis  of  atropine  is  realized  experimentally.  The  al- 
kaloids themselves  are  termed  tropeines.  The  separation  of 
tropic  acid  is  of  the  nature  of  a  saponification,  being  most  easily 
effected  by  alkalies,  as  given  in  full  under  Atropine,  d.  The 
natural  midriatic  alkaloids  having  the  common  formula  have 
been  named,  partly  from  their  sources  in  plants,  as  Atropine, 
Daturine,  Hyoscyamine,  Hyoscine,  Duboisine,  and,  probably  as 
C17H23NO4,  Belladonnine.  Ladenburg  reduces  these  alkaloids 
in  identity  to  the  three  isomers,  Atropine,  Hyoscyamine,  and 
Ilyoscine  (beside  belladonnine).  The  alkaloids  of  the  midriatic 
group,  like  the  Aconite  group  of  alkaloids  and  like  Cocaine,  are 
to  be  treated  with  a  clear  understanding  of  the  fundamental  fact 
cornmcn  to  these  groups,  that  they  are  saponifiable  bodies  —  a  fact 
that  sheds  most  welcome  light  upon  the  long  standing  difficulty 
of  preserving  these  alkaloids  intact  during  operations  for  their 


authorities  classify  the   midriatic    plants    under    the    order    of 
Scroph  ulariaeea3. 


340 


MIDRIATIC  ALKALOIDS. 


separation.  *  Tlie  tropeine  alkaloids,  including  artificial  tropines 
like  Homatr opine,  have  strongly  marked  chemical  characteris- 
tics— including  a  quite  direct  relationship  to  benzene,  as  shown 
by  "  the  odor  test "  ;  and  an  exceptionally  strong  alkalinity,  as 
shown  by  phenol-phthalein. 

The    sources  of  the  three  natural  tropeine  isomers  already 
known  are  as  follows : 


Medicinal  drug,  and  commer- 
cial alkaloid. 

Plant. 

True  alkaloids  (LADENBUBG). 

Belladonna,  root,  leaf. 
"  Atropine." 
"  Heavy  atropine  "  of 
Merck. 
"  Heavy  daturine." 

Atropa    Bella- 
donna. 

Atropine  (larger  part). 
Hyoscyamine. 
In  root,  belladonnine. 
Total,  0.3  to  0.5  per  cent. 
Root  |  more  than  leaves. 

Hyoscyanms,  leaf,  seed. 
"  Hyoscyamine." 
"Light  atropine"  of 
Merck. 

Hyoscyamus 
niger. 
H.  albus. 

Hyoscyamine. 
Hyoscine. 
Total,  0.1  to  0.5$ 

Strammonium,  leaf,  seed. 
"  Daturine."  , 
"Light  daturine." 

Datura  Stram- 
monium. 

Hyoscyamine. 
Atropine  (a  little). 
Total,  0.2  to  0.3$ 

Duboisia. 
"  Duboisine." 

Duboisia    mio- 
poroides. 

Hyoscyamine. 

1  KRAUT,  1863-65:  Ann.  Chem.  Phar.,  128,  280;  133,  87;  Watts' s  Diet.,  5, 
895.  LADENBURG,  in  part  with  MEYER,  SMITH,  and  others,  1879  to  1884.  A 
summary  to  1883  in  Liebig's  Annalen,  217,  74;  Jour.  Chem.  Soc.,  1883,  Abs., 
670;  Proe.  Am.  Pharm.,  32,  316;  Am.  Jour.  Phar.,  55,  463.  Jour.  Chem.  Soc., 
1884,  Abs.,  761. 

Tropine,  the  common  base  of  the  Atropine  group  of  alkaloids,  is  a  deriva- 
tive of  pyridine.  Pyridine,  C5H6N,  is  the  primary  member  of  the  pyridine  se- 
ries, CnH2n-  sN,  and*  the  type  of  the  quinoline  series,  CnH2n_ ,  ,N.  Both  series 
have  great  interest  in  the  chemistry  of  natural  alkaloids,  many  of  which  are 
found  to  be  clearly  placed  in  the  aromatic  group.  There  is  a  great  deal  of 
evidence  now  making  it  probable  that  alkaloids  generally  are  hydrogenized 
derivatives  of  pyridine.  See  under  Cinchona  Alkaloids,  Constitution  of,  and 
Quinoline.  (LADENBURG,  1884,  1885;  A.  W.  HOFMANN.  1884,  1885;  HANTZSCH, 
1884;  KONIGS,  1884.  Review  in  Am.  Chem.  Jour.,  1882-85:  4,  64.  157;  5,  60, 
72;  7,  200. 

Ladenburg  places  the  rational  formula  of  tropine,  as  C6H7(C2H4 .  OH)N(CH3) 
=  C8Hi5NO.  That  is,  in  a  fe^rahydro-pyridine  (C5H9N),  ethylene-hydroxyl 
(C2H4.OH)  and  methyl  (CH3)  take  the  place  of  H2.  And  then  atropine,  or  tro- 
pate  of  tropine,  stands  as  C.Ht(C*H4.WC9H,0«3)N(CH,)  =  C17H23N03. 

The  comparison  with  Aconite  Alkaloids  and  Cocaine,  mentioned  in  the 
text,  is  extended  by  the  fact  that  they  all  yield  either  benzoic  acid  or  a  deriva- 
tive of  benzoic  acid,  by  saponification — the  tropic  acid  from  atropine  saponifica- 
tion  easily  changing,  through  atropic  acid,  to  benzoic  acid. 


PITURINE.  341 

In  belladonna  root  an  alkaloid  other  than  the  "atropine"  of 
commerce  was  found  by  HUBSCHMANN  in  1858,  and  named  Bella- 
donnine.  LADENBURG  (1884)  finds  belladonnine  to  be,  probably, 
the  tropate  of  oxytropine,  C17H23NO4,  an  oxy-atropine.  POEHL 
(1876)  found  the  "daturine"  of  strammonium  to  be  optically 
levo-rotatoryr  while  the  "  atropirie  "  of  belladonna  was  inactive, 
and  several  observers  have  stated  that  the  "  daturine "  is  the 
stronger  of  the  two  in  physiological  effect.  Hager's  Commen- 
tar  (1883)  asserts  that  the  former  reputation  of  "  English  atro- 
pine"  for  superiority  arose  from  its  having  been  made  from 
strammonium,  "  daturine  "  being  more  powerful  than  "  atropine." 
It  will  be  observed  that  Ladenburg  places  the  difference  between 
"  atropine  ''  and  "  daturine  "  chiefly  in  the  larger  proportion  of 
pure  atropine  in  the  former,  and  of  pure  hyoscyamine  in  the  lat- 
ter. Also  the  medicinal  "  hyoscyamine,"  the  total  alkaloid  of 
the  hyoscyamus,  is  generally  reported  to  have  more  intense 
physiological  action  than  the  "  atropine  "  taken  as  total  alkaloid 
of  belladonna  (DUQUESNEL,  1882).  Undoubtedly  these  differ- 
ences in  effect  are  covered  by  greater  differences  of  strength,  due 
to  incomplete  separation  from  impurities  not  alkaloids. 

The  Duboisia  Hopwoodii,  dried  leaves  and  twigs  of  which 
constitute  the  Australian  drug  "  Piturie,"  yields  an  alkaloid 
quite  different  from  duboisine  of  D.  mioporoides,  a  liquid,  vola- 
tile alkaloid,  not  containing  oxygen,  resembling  nicotine,  not 
midriatic,  and  named  Piturine  (LIVERSIDGE,  1881).  (See  under 
Piturine.) 

For  Atropine,  with  the  reactions,  estimation,  etc.,  of  the 
midriatic  group  of  alkaloids,  see  p.  344 ;  for  Hyoscine,  p.  342 ; 
Hyoscyamine^  p.  342;  Hoinatropine  (one  of  the  artificial  alka- 
loids of  the  midriatic  group),  p.  343. 

PITURINE. — CglTgN.1  From  the  Duboisia  Hopwoodii  of 
Australia.  The  dried  leaves  and  twigs  of  this  plant  consti- 
tute the  drug  piturie,  used  by  the  natives,  with  effects  chiefly 
the  same  as  those  of  tobacco.  The  yield  of  alkaloid  is  stated  to 
be  one  per  cent,  of  the  dried  drug.  Piturine  is  a  liquid,  volatile 
alkaloid,  of  oily  consistence,  slightly  heavier  than  water.  It  has 
an  acrid,  burning  taste,  a  tobacco-like  odor,  and  gives  the  physio- 
logical effects  of  tobacco.  Its  reaction  is  strongly  alkaline,  and 
it  neutralizes  acids.  It  is  soluble  "  in  all  proportions  "  of  water, 
alcohol,  and  ether.  It  gives  precipitates  with  the  general  reagents 

LIVERSIDGE,  1881:  Phar.  Jour.  Trans.  [3]  n,  815;  Am.  Jour.  Phar., 
53,  352.  The  literature  of  this  alkaloid  is  chiefly  dependent  upon  the  report  of 
this  author. 


342  MIDRIA  TIC  ALKALOIDS. 

for  alkaloids,  and  differs  from  nicotine  in  its  reactions  with  mer- 
curic chloride,  gold  chloride,  platinic  chloride,  and  in  Palm's  test 
for  nicotine  with  hydrochloric  and  nitric  acids. 

HYOSCYAMINE. — C17H23NO3  =  289.  An  isomer  of  Atropine 
(LADENBURG),  which  it  closely  resembles  (see  p.  344).  For 
sources  and  relations  see  p.  340.  It  will  be  observed  that  the 
distinct  alkaloid  hyoscyamine  forms  a  small  part  of  manufactured 
medicinal  u  atropine,"  a  large  part  of  "  daturine,"  an  especially 
large  part  of  "  light  daturine,"  the  whole  alkaloid  of  "  duboisine," 
and  one  of  the  two  alkaloids  of  the  "  hyoscyamine  "  of  the  mar- 
ket (the  mixed  alkaloids  of  Hyoscyamus  niger),  the  other  alka- 
loid of  this  drug  being  Hyoscine.  The  article  sold  as  "  crystal- 
lized hyoscyamine  "  is  stated  to  consist  mainly  of  true  hyoscya- 
mine, while  "  amorphous  hyoscyamine  "  consists  chiefly  of  the 
alkaloid  hyoscine.  "Hyoscyamine"  is  presented  in  the  Ph. 
Fran,  as  free  alkaloid,  in  crystalline  form,  with  the  "  observa- 
tion" that  the  article  of  commerce  is  commonly  amorphous. 
There  appears  to  be  some  indirect  evidence  that  hyoscyamine 
(true)  is  a  more  potent  midriatic  than  atropine  (see  Atropine,  l>\ 
but  the  greater  activity  of  "  hyoscyamine,"  as  total  alkaloids  of 
Hyoscyamus  niger,  is  mainly  due  to  the  hyoscine,  which  is  a 
more  active  midriatic  than  either  atropine  or  hyoscyamine. 

Hyoscyamine  crystallizes  in  slender,  colorless  needles,  which 
sometimes  radiate  in  groups.  It  melts  at  108°  C.  (236.4°  F.)  Its 
solubilities  are  nearly  the  same  as  those  stated  under  Atropine,  c. 
It  responds  to  the  distinctive  tests  given  under  Atropine.  d,  with 
the  differences  there  stated  for  the  reactions  with  gold  chloride, 
platinum  chloride,  mercuric  chloride,  and  picric  acid.  In  treat- 
ment for  tropine,  with  alkalies,  a  tropine  isomeric  with  that  of 
atropine,  and  a  tropic  acid  identical  with  that  of  atropine,  are 
obtained. 

Hyoscyamine  is  well  separated  from  atropine,  and  less  easily 
from  hyoscine,  by  the  precipitation  with  gold  chloride  (see  un- 
der Hyoscine).  The  separation  from,  liyoscyamub  leaf  and  seed, 
and  methods  of  quantitative  estimation,  are  given  under  Atro- 
pine, e  and  f. 

HYOSCINE.— C17H?3NO3  =  289.  Tropate  of  pseudotropine. 
An  isomer  of  Atropine  (LADEHBUKG),  one  of  the  two  alkaloids 
obtained  from  Hyoscyamus  niger,  leaf  and  seed,  p.  340.  It  has 
been  stated  that  the  so-called  "  amorphous  hyoscyamine  "  of  the 
market  has  consisted  mainly  of  hyoscine.  Hyoscine  hydro- 
bromide,  and  other  salts,  presented  as  such,  in  crystalline  form, 


HOMA  TROPINE.  343 

are  offered  for  sale  for  medicinal  uses.  An  ordinary  dose  by  the 
mouth  is  ^  grain,  a  full  dose  1  grain  ;  it  is  a  calmative,  with 
effects  distinct  from  those  of  atropine ;  its  midriatic  effects  are 
more  rapid  than  those  of  atropine ; J  obtained  by  a  quantity 
smaller  than  required  of  atropine.3 

Hyoscine,  uncornbined,  is  in  syrupy  or  amorphous  solid  state, 
colorless,  forming,  with  ordinary  acids,  solid  salts.  The  hydro- 
bromide  crystallizes  in  prisms  without  color ;  the  hydriodide  in 
pale  golden  prisms.  The  hydriodide  is  levo-rotatory.  In  solu- 
bilities hyoscine  resembles  Atropine.  Hyoscine  responds  to  the 
distinctive  tests  given  under  Atropine,  d.  The  hyosoine  auro- 
chloride  is  less  soluble  and  less  lustrous  than  the  hyoscyamine 
aurochloride  ;  it  crystallizes  in  yellow  prisms  and  melts  at  198°  C. 
(the  aurochloride  of  atropine,  lustreless,  nearly  insoluble  precipi- 
tate, melts  at  185°  C. ;  that  of  hyoscyamine,  lustrous  golden, 
melts  at  Io9°  C. — LADENEURG).  The  platinochloride  of  hyoscine 
forms  small  octahedral  crystals,  soluble  in  water  and  in  alcohol 
(of  hyoscyamine,  triclinic  crystals ;  of  atropine,  monoclinic  crys- 
tals). Iodine  solution  in  potassium  iodide  gives  a  dark-colored, 
oily  product.  Potassium  ferrocyanide  gives  a  white,  amor- 
phous precipitate.  The  precipitate  with  Mayer's  solution  is 
yellowish  ;  with  mercuric  chloride,  amorphous,  sometimes  oily 
liquid. 

Treated  with  barium  hydrate  for  tropine,  as  given  under 
Atropine,  d.  the  isome^  named  pseudotropine  is  obtained.  This 
crystallizes  in  rhombohedrons,  melts  at  106°  C.,  and  boils  at 
241°  C.  (tropine  melts  at  62°  C.),  dissolves  readily  in  water  and 
in  chloroform,  sparingly  in  ether.  The  aurochloride  melts  at 
198°  C.  The  tropic  acid  of  hyoscine  is  identical  with  that  of 
hyoscyamine  and  atropine. 

LAI/ENEURG  separates  hyoscine  from  hyoscyamine  by  forma- 
tion of  the  aurochloride,  which  is  crystallized  several  times  for 
removal  of  the  more  soluble  hyoscyamine  salt  (atropine  auro- 
chloride, if  present,  being  removed  at  first  as  a  nearly  insoluble 
precipitate).  The  crystals  obtained  are  decomposed  with  hydro- 
gen sulphide,  the  filtrate  made  alkaline  with  potassium  carbonate 
and  shaken  with  chloroform,  and  the  resulting  chloroform  solu- 
tion evaporated  to  give  a  residue  of  the  hyoscine. 

HOMATROPINE. — C16H21NO3.  Phenyl  glycollic  tropeine.  One 
of  a  group  of  artificial  alkaloids  called  tropeines,  and  produced  by 

'H.  C.  WOOD,  1885:  Therapeutic  Gazette,  9,  1,  594,  760. 

2  By  one-fifth  the  quantity  (!)  EMMEET.     See  also  HIRSCHBEEG,  1881. 


344  MIDRIATIC  ALKALOIDS. 

LADENBUKG  (1880)  by  uniting  tropine,  the  common  base  of  natu, 
ral  atropine  and  hyoscyamine,  with  various  acidulous  and  other 
radicals,  p.  339.  Homatropine  is  formed  by  the  union  of  tro- 
pine, C8H15KO,  with  mandalic  acid,  C8H8O3,  a  molecule  of 
water  being  separated.  Mandalic  acid  is  formed  from  amygdalin 
by  digestion  with  hydrochloric  acid,  and  in  other  ways,  and  has 
the  structure  C6H5 .  CHOH .  CO2H,  phenyl-gly collie  acid.  When 
mandalate  of  tropine  is  digested  with  hydrochloric  acid,  the  ele- 
ments of  water  are  withdrawn  and  homatropine  is  produced. 
C8H15NO.C8H8O3=:Ci6H21NO3  +  H2O.  Since  about  1882 
homatropine  hydrobromide  lias  been  used  medicinally.  It  is  an 
active  midriatic ;  its  effects  do  not  continue  as  long  as  those  of 
atropine,  and  in  the  same  doses  it  is  less  poisonous. 

Homatropine  is  crystallizable  in  prisms  from  a  solution  in 
absolute  ether ;  has  a  melting  point  of  about  98°  C. ;  is  hygro- 
scopic and  very  deliquescent ;  and  it  is  ordinarily  obtained  only 
in  the  state  of  a  thick  liquid.  It  dissolves  some  in  water,  but 
is  not  freely  soluble  in  water.  It  is  freely  soluble  in  ether  and  in 
chloroform.  The  nydrobromide,  C16H21NO3.HBr,  crystallizes 
in  flat,  rhombic  prisms  forming  wart-like  aggregations,  perma- 
nent in  the  air.1  It  is  soluble  in  ten  parts  of  water,  the  solution 
not  readily  suffering  change.  The  hydrochloride  is  very  soluble 
in  water,  and  is  crystallizable.  The  sulphate  crystallizes  in  silky 
needles. 

With  solutions  of  homatropine  salts  potassium  mercuric 
iodide  gives  a  white,  curdy  precipitate ;  gold  chloride,  a  pre- 
cipitate, C16H21NO3 .  HC1 .  AuCl3 ,  at  first  of  oily  consistence, 
soon  crystallizing  in  prismatic  forms ;  picric  acid,  a  precipitate 
soon  becoming  crystalline.  Platinic  chloride  gives  a  precipitate 
only  in  concentrated  solutions,  but  fine  crystals  of  the  double 
salt  are  formed  (with  the  hydrochloride). 

ATROPINE. — C17H23NO8  =  289.  Tropate  of  tropine,  and  pro- 
bably C5H7(C2H4O .  CO .  CHC6H5.CH2  ,OH)NCH3  (LADENBURG). 
For  sources  and  chemical  structure  see  p.  339.  Forms  the  larger 
part  of  pharmacoposial  "  atropine " ;  a  smaller  portion  of  the 
"daturine"  or  "atropine"  obtained  from  strammonium;  and 
an  isomer  of  the  alkaloids  hyoscyamine  and  hyoscine. 

Atropine  and  its  isomers  (hyoscyamine,  hyoscine)  are  identified 
as  midriatics  by  the  organoleptic  test  (b,  d) ;  as  tropine  tropates 
by  Vitali's  test,  the  crystallizable  bromine  precipitate,  the  phenol- 

'F.  B.  POWER,  1882:  a  summary  upon  homatropine,  Am.  Jour.  Phar., 
54,  145. 


A  TROPINE.  345 

phthalein  reaction,  the  test  with  mercuric  chloride,  and  (if  in  suf- 
ficient quantity)  by  the  odor  tests  (d).  Atropine  and  its  isomers 
are  distinguished  from  each  other  by  the  precipitation  with  gold 
chloride,  and  by  differences  in  reactions  with  mercuric  chloride, 
platinum  chloride,  and  picric  acid,  that  with  gold  chloride  being 
serviceable  for  separation.  Hyoscyamine  from  atropine  by  their 
melting  points.  Atropine  and  its  isomers  are  separated  from 
crude  drugs,  extracts,  plasters,  animal  tissues,  the  urine,  etc.,  by 
general  and  special  methods  given  under  e  •  and  are  estimated 
^n  quantity,  by  gravimetric,  volumetric,  or  physiological  method, 
as  laid  down  under  f.  Tests  for  impurities,  g. 

a  — Colorless  or  white,  lustrous  acicular  crystals,  or  a  crystal- 
line or  nearly  amorphous  powder.  In  commerce  sometimes  yel- 
lowish. By  exposure  to  air  it  acquires  at  length  a  yellowish  or 
even  violet  tint.  Melts  at  114°  0.  (237.2°  F.)  (LADENBUKG, 
1881)  (U.  S.  Ph.)  At  115°-115.5°  C.  (239°-240°  F.)  (E.  SCHMIDT, 
1880).  The  medicinal  atropine  heated  alone  on  a  bath  of  glyce- 
rine begins  to  melt  at  about  104°  C.  and  is  entirely  melted  at 
113°  C.  (SQUIBB,  1885).  The  artificial  alkaloid  melts  at  113.5°  C. 
(LADENBUKG,  1883).  At  123°  C.  gives  a  faint  mist  of  micro- 
scopic sublimate,  not  crystalline  (BLYTH).  Vaporizes  at  about 
140°  C,,  giving  white  fumes  and  an  oily  sublimate.1  Vaporizes 
slightly  with  boiling  water,  and  even  with  boiling  alcohol  (DuA- 
GENDORFF).  When  dry  does  not  lose  weight  at  100°  C  (DUNSTAN 
and  RANSOM,  1886).  Upon  ignition  it  is  easily  dissipated,  with- 
out residue. 


b. — Without  odor,  it  has  a  disagreeably  bitter  and  acrid  taste. 
The  largest  medicinal  dose  is  about  -fa  grain  (Ph.  Germ.),  and  it 
is  an  active  deliriant  poison. — Solutions  for  application  to  the 
eye  should  never  exceed  the  strength  of  one  per  cent.,  and  for 
the  test  of  midriasis  should  be  far  more  dilute  than  this.  The 
cat  is  a  favorable  subject  for  the  test.  A  solution  in  130000 
parts  of  water,  applied  to  one  eye  of  a  cat,  suffices  for  dilatation 
(DRAGENDORFF).  With  frogs  a  solution  of  1  to  250  obtains  dila- 
tation, commencing  in  about  five  minutes  (v.  GKAEFE).  Dr.  E. 
R.  SQUIBB  (1885  s)  reports  the  following  results  upon  the  human 
eye,  on  applying  to  one  eye  of  each  person  one  drop  of  a  solu- 

1  As  to  the  form  of  the  crystals,  formed  under  the  microscope,  see  HELWIG, 
1864;  A.  PERCY  SMITH,  1886. 

*Ephemeris,  2,  855.     See  also  "  Blyth  on  Poisons,"  1885,  New  York,  p. 


MIDRIATIC  ALKALOIDS. 


tion  of  atropine  sulphate  diluted  nearly  in  the  proportions  here 
stated : 


Dilution. 

Individuals 
under  trial. 

Commencing  dilatation. 

2280  parts  

Several. 

15  to  18  minutes. 

4560      "     

Several. 

30  minutes. 

9120      "     

Two. 

About  40  minutes. 

18240      u     

Two. 

50  and  32  minutes. 

45600  '    "           

Two. 

45  minutes  each 

91200      "       

Five. 

In   two,  no  effect  \ 

in  three,  effect  in 
about  1  hour. 

The  same  persons  were  not  used  in  all  experiments,  and 
eighteen  persons  in  all  were  employed.  The  sulphate  of  atro- 
pine was  "  about  the  best  obtainable  in  the  market."  A  sample 
of  crude  atropine  fresh  from  an  assay  of  belladonna  leaf  gave 
earlier  dilatations,  and  in  the  last  trial,  by  dilution  to  90800  parts, 
gave  dilatation  in  45  and  50  minutes.  The  investigator  esti- 
mated that  an  effect  in  50  minutes  was  obtained  by  action  of 
about  0.000000427  gramme  of  the  alkaloid. — Atropine  is  ex- 
creted by  the  urine  to  some  extent,  being  found  in  that  fluid 
after  administration. 

In  frogs  the  constitutional  effects  of  atropine  are  peculiar, 
including  first  paralysis,  and,  after  a  day  or  later,  tetanic 
spasms. 

c.— Atropine  is  soluble  in  600  parts  of  water  at  15°  C.  (59°  F.), 
or  in  35  parts  of  boiling  water  ;  soluble  in  glycerine,  and  freely 
soluble  in  alcohol,  chloroform  (3  parts),  ether  (60  parts),  amyl 
alcohol,  and  benzene  (42  parts),  scarcely  soluble  in  petroleum 
benzin  or  carbon  disulphide.  Fixed  oils  dissolve  it.  Aqueous 
solutions  are  not  very  stable. — It  has  a  decided  alkaline  reaction, 
exhibited  not  only  with  litmus-paper  in  common  with  most  alka- 
loids, but  with  phenol-phthalein,  a  difference  of  atropine  and  its 
isomers  from  other  alkaloids  (FLUCKIGEK,  1886).  Its  special 
alkalinity  is  also  shown  by  its  reaction  with  mercuric  chloride 
(see  d). — Its  salts  with  the  stronger  acids  are  freely  soluble  in 


1  GRAEFE  gives  1  to  28000  as  the  dilution  for  moderate  dilatation  commenc 
ing  in  |  to  1  hour. 


A  TROPINE.  347 

water  or  alcohol ;  not  soluble  in  chloroform  or  ether.  At  50° 
to  60°  C.  both  benzene  and  amyl  alcohol  extract  a  little  atropine 
from  acidulous  solution  (DRAGENDORFF).  The  sulphate  crystal- 
lizes anhydrous,  (C17H23NO3)2H2SO4.  The  salicylate  is  of  neu- 
tral reaction,  not  crystallizable,  deliquescent,  not  stable  in  solu- 
tion. Dr.  SQUIBB  (1885)  advises  the  preservation  of  aqueous  so- 
lutions of  atropine  sulphate  by  salicylic  acid,  a  cold  saturated 
solution  of  which  is  taken  for  one  half  of  the  solvent. 

d. — In  evidence  of  the  presence  of  atropine,  the  physiological 
test  for  the  pupil-dilating  alkaloids,  chiefly  atropine  and  its  iso- 
mers  (p.  340),  deserves  to  be  named  first.  Of  bodies  other  than 
the  solariaceous  alkaloids  it  is  to  be  observed  that  cocaine,  digi- 
talis and  its  active  principles,  and  conine  dilate  the  pupil  of  the 
eye.  Aconitine  has  a  variable  effect  of  dilatation.  Nicotine  is 
stated  to  first  dilate  and  then  contract  the  pupil.  SELMI  (1877- 
1879)  found  certain  ptomaines  to  dilate  the  pupil.  The  visual 
effect  of  the  solanacese  seems  to  have  been  imperfectly  known 
prior  to  the  last  quarter  of  the  eighteenth  century.1  The  limits 
are  given  under  b.  Dilatation  from  v  solution  not  stronger  than 
1  in  500  parts  causes  little  inconvenience  to  the  human  eye.  The 
eye  of  the  cat  is  preferable.  In  testing  the  separated  product  of 
an  analysis,  an  aqueous  solution  is  obtained  of  the  free  alkaloid 
or  its  salt  (sulphate),  neutral  or  only  very  feebly  alkaline  in  reac- 
tion, and  not  strongly  saline  with  any  metallic  salts,  and  not  al- 
coholic. A  drop  or  two  is  let  fall  into  one  of  the  eyes,  the  time 
noted,  and  from  time  to  time  the  width  of  the  one  pupil  is  com- 
pared with  that  of  the  other. 

VitaWs  test  is  made  as  follows :  The  dry  residue  is  treated 
with  a  little  fuming  nitric  acid,  then  dried  on  the  water-bath,  and 
when  cold  touched  with  a  drop  of  solution  of  potassium  hydrate 
in  absolute  alcohol,  when,  in  evidence  of  atropine  (or  one  of 
its  isomers),  a  violet  color  will  appear,  slowly  changing  to  a  dark 
red.  Strychnine  gives  a  red,  brucine  a  greenish  color.  The 
violet  color  is  distinctive  for  atropine  among  all  important  alka- 
loids, and  reaches  the  limit  of  0.000001  gram  of  the  alkaloid  (D. 
YITALI,  1880).  ARNOLD  (1882)  in  this  test  uses,  instead  of  fum- 
ing nitric  acid,  first  a  drop  of  sulphuric  acid  rubbed,  cold,  to 
moisten  the  residue,  and  then  a  solid  particle  of  sodium  nitrite. 
With  atropine  the  violet  does  not  appear  till  the  alcoholic  potash 
is  applied  (strychnine,  orange-red).  Colors  appearing  before  the 


1  See  an  interesting  historical  paper  by  ROBERT,  1886:  Therapeutic  Gazette, 
10  445. 


348  MIDRIA  TIC  A  LKA  L  OIDS. 

alcoholic  potash  is  added  (narceine,  morphine,  narcotine)  render 
the  test  inapplicable. 

Phosphomolybdate  of  sodium  gives  a  yellow  precipitate, 
visible  in  dilution  to  4000  parts  (DRAGENDORFF),  dissolving  in 
ammonia  with  a  blue  color.— Iodine  in  potassium  iodide  solu- 
tion, better  applied  to  the  hydrochloride  solution,  gives  a  precipi- 
tate of  the  color  of  the  iodine  solution,  oily  at  first  and  afterward 
crystalline  (LADENBURG),  distinct  in  solution  of  8000  parts  of 
water  and  visible  in  solution  of  50000  parts  (JORGENSEN),  more 
complete  than  precipitation  by  phosphoniolybdate  (DUNSTAN  and 
RANSOM),  dissolved  by  boiling  alcohol,  from  which  solvent  it 
crystallizes,  blue-green,  as  pentahydriodide.  For  separation  of 
the  alkaloid  from  this  precipitate  see  e. — Bromine  dissolved  to 
saturation  in  hydrobrornic  acid  solution  gives  a  yellow  precipi- 
tate, at  first  amorphous,  obtained  in  a  solution  of  the  alkaloid  in 
10000  parts  of  water  (WORMLEY  '),  not  dissolved  by  acids  or  fixed 
alkalies.  The  amorphous  precipitation  is  common  to  most  alka- 
loids, but  the  precipitate  of  atropine  and  its  isomers  is  character- 
istic in  this  (Wormley)  that  it  soon  becomes  crystalline,  and  under 
a  magnifying  power  of  75  to  125  diameters  presents  distinctive 
forms  of  lanceolate  leaf-like  crystals,  which  gradually  group  to- 
gether like  the  petals  of  a  flower.  These  crystals  may  be  obtained 
from  spontaneous  evaporation  of  one  grain  of  a  solution  diluted 
to  25000  parts.  Imperfect  crystallization  gives  only  irregular 
needles  and  granules.  Repeated  trials  are  made  by  dissolving 
in  a  drop  of  water  and  crystallizing  anew. 

Phenol-phthalein  as  an  indicator  applied  to  the  free  alkaloid, 
as  to  the  chloroformic  or  ethereal  residue,  gives  the  scarlet  color 
in  evidence  of  alkalinity,  this  reaction  being,  according  to  Prof. 
FLUCKiGER,2  common  to  atropine  and  its  isomers  and  hoinatro- 
pine,  and  a  distinction  from  all  alkaloids  in  general  use. 

Mercuric  chloride  in  a  5  per  cent,  solution  in  50  per  cent, 
alcohol,  avoiding  an  excess,  gives  a  red  precipitate  containing 
mercuric  oxide  (GERRARD,  1884 ;  SCHWEISSINGER,  1885  ;  FLUCKI- 
GER, 1886).  On  standing  tabular  crystals  of  atropine  mercuric 
chloride  are  obtained.  With  hyoscyamine  the  precipitate  appears 
only  after  warming  (Schweissinger).  With  this  reagent  most 
alkaloids  give  white  precipitates ;  morphine  and  codeine,  yellow 
ones.  Of  course  inorganic  bodies  of  alkaline  reaction  must  be 
absent,  and  the  alkaloid  must  be  free. — Potassium  mercuric 
iodide,  or  Mayer's  solution,  gives  a  whitish,  curdy  precipitate, 

1  "  Microchemistry  of  Poisons,"  3d  ed.,  1885,  641. 

*1886:  Phar.  Jour.  Trans.  [3]  15,  601;  Am.  Jour.  Phar.,  58,  129. 


A  TROPINE.  349 

Jiardly  visible  in  solution  diluted  to  4000  parts  (DRAGENDORFF). — 
Potassium  bismuthic  iodide,  a  precipitate  visible  in  solution 
diluted  to  25000  parts  (THRESH,  1880).  Gold  chloride,  a  lustre- 
less precipitate,  discernible  in  solution  diluted  to  20000  parts, 
melting  at  135°  C.  (LADENBURG),  C17H24NO3.  AuCl4.  The  hy- 
oscvamine  precipitate,  with  gold  chloride,  has  a  golden  lustre  and 
melts  at  159°  C.  (LADENBURG).  Platinum  chloride  (with  hydro- 
chloric acid)  precipitates  only  very  concentrated  solutions  of 
atropine  ;  the  crystals  of  chloroplatinate  are  monoclinic  and  melt 
at  207°  C.  (hyoscyamine  chloroplatinate  crystals  are  tricliriic) 
(LADENBURG).  Picric  acid  (HAGER)  with  the  "English  atro- 
pine "  (p.  341)  gave  an  amorphous  turbidity,  which,  after  heating 
to  dissolve  it,  crystallizes  in  rectangular  plates  on  cooling.  The 
"  German  atropine,"  treated  in  the'same  way,  gave  the  rectangu- 
lar plates  at  once.  Tannic  acid  precipitates  neutral  and  con- 
centrated solutions  of  atropine. — The  dilute  caustic  alkalies,  and 
sodium  and  potassium  normal  carbonates,  precipitate,  from  con- 
centrated solutions  of  atropine,  a  part  of  the  alkaloid,  soluble  in 
an  excess  of  a  caustic  alkali.  On  heating  the  fixed  alkali  solu- 
tions ammonia  is  finally  evolved  by  decomposition  of  the  atro-_ 
pine.  Ammonium  carbonate  and  fixed  alkali  bicarbonates  give 
no  precipitates.  Concentrated  sulphuric  acid  gives  no  color. 

Atropine,  in  common  with  its  isomers,  is  easily  saponified,  or 
resolved  by  alkalies  into  its  TROPINE  and  TROPIC  ACID.  (See  un- 
der Midriatic  Alkaloids.)  The  aqueous  solution  of  alkaloid  is 
digested  with  barium  hydrate  at  60°  to  80°  C. ;  then  carbon 
dioxide  is  passed  in  and  the  barium  carbonate  filtered  out ;  the 
filtrate  is  acidified  with  hydrochloric  acid  and  shaken  with  ether, 
in  two  portions ;  the  separated  ether  is  allowed  to  evaporate 
spontaneously,  when  tropic  acid  is  obtained  in  the  residue.  The 
aqueous  solution  left  after  removing  the  ether  is  now  treated 
with  potassium  hydrate  solution  to  an  alkaline  reaction,  and  the 
liquid  again  extracted  with  ether,  which  is  allowed  to  separate 
after  shaking,  drawn  off,  and  evaporated  in  a  warm  place.  The 
residue  will  contain  the  tropine.  Instead  of  digestion  with  barium 
hydrate,  digestion  with  hydrochloric  acid  may  be  employed. 
Tropic  acid  melts  at  117°  C.  Heated  with  dilute  solution  of 
permanganate  it  gives  odor  of  bitter-almond  oil,  and  on  further 
treatment  benzoic  acid  is  formed.  Tropic  acid  is  easily  changed, 
by  loss  of  H^O,  to  atropic  acid,  C9H8O2,  isomeric  with  cinnamic 
acid.  Tropine  crystallizes  from  anhydrous  ether  in  the  rhombic 
system,  and  melts  at  62°  C.  It  is  hygroscopic,  in  ordinary  resi- 
dues assumes  an  oily  consistence,  is  freely  soluble  in  water,  in 
alcohol,  and  in  ether,  has  a  strong  alkaline  reaction,  gives  an  odor 


350  MLDRIATIC  ALKALOIDS. 

when  heated,  and  forms  definite  salts  with  acids.  The  chloro- 
platinate  crystallizes  with  orange-red  color,  dissolves  in  water, 
not  in  alcohol. 

The  odor  test,  by  production  of  benzoic  or  salicylic  aldehyde, 
is  made,  in  several  ways,  by  concentrated  sulphuric  acid  alone,  or 
by  this  followed  by  dichromate  or  other  oxidizing  agent,  and  is 
directed  as  follows  in  the  Ph.  Germ. :  "  0.001  grarn  [at  the  least] 
of  the  atropine  sulphate,  in  a  small  test-tube,  is  heated  until 
white  vapor  appears,  then  1.5  grams  of  sulphuric  acid  is  added, 
and  heated  until  it  commences  to  brown.  Now  on  adding  2 
grams  of  water  an  agreeable  odor  is  perceived,  and  by  further 
addition  of  a  crystal  of  permanganate  of  potassium  the  odor  of 
bitter-almond  oil  is  obtained."  This  reaction,  by  whatever  reagents, 
is  not  a  delicate  one,  and  often  fails,  but  it  is  characteristic  in 
comparison  of  ordinary  alkaloids. 

e. — Separations. — Aqueous  solutions  of  atropine,  in  concen- 
tration by  heat  and  in  standing,  aie  liable  to  suffer  very  slight 
waste  of  the  alkaloid  by  its  decomposition,  but  this  waste  is  less 
for  salts  with  stable  acids  than  it  is  for  the  free  alkaloid,  and  in 
ordinary  evaporations  is  prevented  by  adding  enough  dilute  sul- 
phuric acid  to  neutralize  or  barely  to  acidulate  the  liquid. — 
Acidulous  solutions  of  atropine  can  be  washed  by  petroleum 
benzin  without  loss  of  the  alkaloid,  and  washed  by  chloroform  or 
ether  with  only  so  much  loss  as  results  from  the  slight  misci- 
bility  of  the  water  with  these  solvents.  Chloroform  or  ether, 
preferably  the  former,  or,  if  separations  require,  benzene  or  amyl 
alcohol,  by  agitation  (in  repeated  portions)  with  aqueous  solu- 
tions made  alkaline,  will  extract  the  alkaloid  almost  without 
waste  The  certainty  of  complete  separation  is  assured  by  a 
negative  result  in  testing  the  aqueous  solution  with  phosphomo- 
lybdate,  or  iodine  in  potassium  iodide,  or  a  residue  oil  evaporat- 
ing a  portion  by  Vitali's  method.  Also,  it  is  important  to  remem- 
ber that  when  an  acidulous  solution  is  made  alkaline  a  salt  is 
formed,  as  ammonium  sulphate,  and  such  salt  will  be  carried  into 
chloroform  or  ether  or  amyl  alcohol,  and  on  evaporation  of  the 
solvent  a  crystalline  residue  of  the  salt  will  be  obtained.  If  the 
salt  be  ammonium  or  other  alkali  sulphate,  the  atropine  is  safely 
separated  from  the  residue  by  solution  in  absolute  alcohol. 
Again,  water  acidulated  with  sulphuric  or  hydrochloric  acid, 
agitated  with  a  solution  of  free  atropine  in  chloroform  or  other 
above-named  solvent,  gradually  transfers  the  alkaloid  to  the 
aqueous  solution.  The  remaining  chloroforrnic  or  ethereal  liquid 
is  tested,  as  to  the  progress  of  the  separation,  by  subjecting  a 


ATROPlNb.  351 

residue  from  a  small  portion  to  Yitali's  test.  An  aqueous  solution 
so  obtained  may  be  precipitated  by  iodine  in  potassium  iodide 
solution  for  estimation  of  the  alkaloid,  as  directed  on  p.  354. 

In  separating  the  aqueous  layer  from  an  under-layer  of  chlo- 
roform, or  from  an  over-layer  of  ether  or  benzene,  a  "  separator  " 
made  for  the  purpose  is,  on  some  accounts,  the  most  convenient 
vessel,  but  the  use  of  a  large,  strong  test-tube,  or  test-glass  on 
foot,  with  the  wash  bottle  fittings  for  siphon-decantation,  is  very 
satisfactory.  These  forms  of  apparatus  are  figured  and  described 
under  Alkaloids,  pp.  35,  36. 

For  separations  from  belladonna  root  and  leaves  DUNSTAN 
and  RANSOM  (1884,  1885)1  direct  as  follows  :  u  Twenty  grams  of 
the  dry  and  finely  powdered  root  are  exhausted  by  hot  percola- 
tion with  a  mixture  of  equal  parts  by  volume  of  chloroform  and 
absolute  alcohol;  and  if  an  extraction  apparatus  is  used  about 
60  c.c.  of  the  mixture  is  required.  The  percolate  is  agitated  with 
two  successive  25  c.c.  of  distilled  water  [acidulation  having  been 
found  unnecessary],  which  [the  watery  layers]  are  separated  in 
the  usual  way.  These  are  mixed  and  well  agitated  with  chloro- 
form to  remove  the  last  traces  of  mechanically  adherent  coloring 
matter.  The  chloroform  is  separated,  the  aqueous  liquid  rendered 
alkaline  with  ammonia  and  agitated  with  two  successive  25  c.c. 
of  chloroform,  which  are  separated,  mixed  and  agitated  with  a 
small  quantity  of  water  (rendered  faintly  alkaline  with  ammonia) 
to  remove  adherent  aqueous  liquid.  The  chloroform  is  then 
evaporated  and  the  residue  dried  over  a  water-bath  until  the 
weight  is  constant,  which  usually  occupies  a  little  less  than  an 
hour."  The  alkaloid  is  obtained  in  white,  silky  crystals,  for 
weight,  and  by  trial  found  pure  alkaloid.  For  the  leaves  "  20 
grams,  dried  and  finely  powdered,  are  well  packed  in  an  extrac- 
tion apparatus,  and  exhausted  with  about  100  c.c.  of  absolute 
alcohol.  The  alcoholic  liquid  is  diluted  with  about  an  equal 
volume  of  water  made  slightly  acid  with  hydrochloric  acid.  The 
chlorophyl,  fat,  etc.,  are  then  removed  from  the  slightly  warmed 
liquid  by  repeatedly  extracting  it  with  chloroform  until  nothing 
further  is  removed  by  the  solvent.  The  aqueous  liquid  is  made 
alkaline  with  ammonia,  and  the  alkaloids  extracted  by  chloro- 
form, by  evaporating  which  a  residue  of  pure  alkaloid  is  obtained, 
and  dried  by  heating  it  at  100°  C.  until  a  constant  weight  is 
attained." 

'From  the  Root:  Phar.  Jour.  Trans.  [3]  14,  623;  Am.  Jour.  Phar.,  56, 
279.  From  the  Leaves  and  the  Extract:  Phar.  Jour.  Trans.  [3]  l6f  237,  238; 
Am.  Jour.  Phar.,  57,582,  584.  Additional  report,  and  discussion  by  Messrs. 
GERRARD,  REDWOOD,  and  others,  Phar,  Jour.  Trans.,  1886  [3]  16,  777,  786. 


352  MIDRIATIC  ALKALOIDS. 

Dr.  E.  R.  SQUIBB  a  exhausts  finely  powdered  root  or  leaves  of 
belladonna  with  alcohol  slightly  acidulated  with  sulphuric  acid, 
as  follows :  50  grams  powdered  leaves  are  moistened  with  32 
grams  alcohol  of  sp.  gr.  0.820  to  which  about  three  drops 
(0.1  gram)  of  sulphuric  acid  have  been  added.  Pack  in  a  cylin- 
drical percolator  and  exhaust,  most  readily  by  a  water-pump, 
with  alcohol  not  acidulated,  of  which  about  300  c.c.  will  be  re- 
quired. Of  the  powdered  root  50  grams  are  moistened  with  15 
to  20  grams  of  strong  alcohol  acidulated  with  three  drops  of  sul- 
phuric acid,  and  packed  rather  lightly  unless  an  efficient  pump 
can  be  used  in  the  percolation.  The  percolate  is  evaporated  in  a 
shallow  dish  over  the  water-bath  until  alcohol  ceases  to  be  per- 
ceptible in  the  vapor;  the  liquid  is  diluted  while  warm  with 
25  c.c.  of  water  to  which  one  or  two  drops  of  sulphuric  acid  have 
been  added ;  the  mixture  stirred  well  and  transferred  to  a  sepa- 
rator, rinsing  the  dish  with  one  or  two  c.c.  of  water.  Wash  the 
dish  with  two  or  three  portions  of  chloroform,  about  30  c.c.  in 
all,  stirring  to  take  up  the  residue,  transfer  the  whole  to  the  sepa- 
rator, acidulate  with  about  three  drops  more  of  sulphuric  acid, 
and  agitate  the  whole  by  active  shaking  for  about  five  minutes, 
"  not  so  very  vigorous  as  to  emulsify  the  liquids  "  to  an  extent 
preventing  separation  afterward.  Emulsion  occurs  in  the  assay 
of  the  leaves,  not  in  that  of  the  root.  "  If,  after  standing  at  rest 
for  an  hour,  the  separation  shall  not  have  begun,  add  three  drops 
more  of  acid,  again  agitate  for  a  minute  or  two,  and  again  set  at 
rest  for  an  hour.  K  the  emulsion  still  does  not  begin  to  sepa- 
rate, add  10  c.c.  more  of  water  and  of  chloroform,  again  agitate 
and  set  at  rest."  "  The  stronger  the  alcohol  used  the  less  of  this 
emulsifying  matter  is  carried  into  the  extract.  An  alcohol  of 
sp.  gr.  0.814  used  for  exhaustion  of  the  powder  never  gave  any 
trouble  from  emulsifying."  After  the  chloroform  layer  (dark 
colored)  is  obtained  and  drawn  off,  the  aqueous  liquid  is  washed 
with  fresh  portions  of  chloroform,  of  10  c.c.  each,  until  the  chlo- 
roformic  layer  is  obtained  nearly  colorless.  The  total  chloro 
formic  washings  are  now  agitated  with  15  c.c.  of  water  acidulated 
with  a  drop  of  sulphuric  acid,  and  after  separation  by  rest  the 
aqueous  layer  is  taken  off  and  added  to  the  main  watery  solution 
of  alkaloidal  sulphate.  This  is  now  agitated,  in  the  separator, 
with  20  c.c.  of  fresh  chloroform  and  as  much  as  6  grams  of  crys- 
tallized sodium  carbonate,  the  last  added  in  small  portions  to 
avoid  frothing  over,. until  a  decided  alkaline  reaction  is  obtained. 
After  agitation  arid  rest  the  chloroformic  layer  is  drawn  off  into 

*Ephemeris,  2,  849,  Sept.,  1885. 


ATROP1NE.  353 

a  tared  ben>er.  A  second  treatment  with  10  c.c.  more  of  chloro- 
form is  made,  this  chloroform  being  added  to  the  first,  and  the 
tared  beaker  is  set  in  a  warm  place  for  the  spontaneous  evapora- 
tion of  the  chloroform.  The  beaker  is  then  turned  on  its  side  in 
a  warm  place,  and  the  residue,  sometimes  crystalline,  sometimes 
varnish- like,  is  dried,  to  weigh  as  atropine. 

For  Ilyoscyamus  leaves  either  method  above  given  for  bella- 
donna leaves  may  be  employed.  ITyoscyamus  seeds  are  first 
freed  from  fats  by  exhausting  the  powder  with  petroleum  benzin 
(DRAGENDORFF).'  Prollius's  fluid,  a  mixture  of  88  parts  of  ether, 
i  of  ammonia-water,  and  8  of  alcohol,  may  be  used  to  exhaust 
the  drug  in  separation  of  atropine  and  its  isomers.  Dragendorff 
(1876-1877)  objects  to  the  use  of  chloroform  upon  the  acidulous 
solution  of  hyoscyamus  to  remove  impurities,  on  the  ground  that 
this  solvent  takes  some  alkaloid  from  acidified  liquids.  He  re- 
commends, instead  of  chloroform,  benzin,  benzene,  or  amyl  alco- 
hol upon  the  acid  solution,  and  uses  chloroform  (or  benzene),  after 
making  alkaline,  to  take  up  the  alkaloids. 

DUNSTAN  and  RANSOM,  in  the  report  quoted  on  p.  351,  give  a 
separation  of  the  alkaloid  from  alcoholic  extract  of  belladonna 
leaves  as  follows  :  "  1  to  2  grams  of  the  extract  are  warmed  with 
dilute  hydrochloric  acid  until  as  much  as  possible  is  dissolved. 
The  mixture  is  filtered,  preferably  through  glass  wool  or  cotton 
wool,  and  the  residue  washed  with  hot  dilute  hydrochloric  acid 
until  nothing  further  is  dissolved.  The  acid  liquid  is  then  re- 
peatedly agitated  with  chloroform,  which,  when  evaporated  and 
dried  at  100°  C.,  leaves  a  residue  of  pure  alkaloid."  (Compare 

SCHWEISSINGER,  1885.) 

In  quantitative  separation  of  the  alkaloids  from  belladonna 
plasters  (the  mass  of  which  is  usually  insoluble  in  alcohol),  a 
weighed  portion  of  the  plaster  is  macerated  in  chloroform  several 
hours,  with  addition  of  enough  ammonia  to  give  an  alkaline  reac- 
tion, the  plaster-cloth  is  macerated  again,  and  washed,  in  chloro- 
form, then  dried  and  weighed  to  obtain  by  difference  the  weight 
of  plaster-mass  taken.  The  chloroformic  liquid  and  washings, 
with  all  the  suspended  matters  liberated  from  the  plasters,  are 
now  shaken  out  (in  a  separator)  with  two  or  three  successive  por- 
tions of  water  acidulated  with  sulphuric  acid,  the  mixture  set  at 
rest,  and  the  aqueous  layer  drawn  off.  If  the  partly  emulsified 
mixture  resists  separation  after  standing  some  hours,  it  may  be 
warmed  to  near  the  boiling  point  of  the  chloroform  (by  immers- 

1  Further  see  DUQUESNEL,  1882:  /.  Pharm.  [5]  5,  131;  Jour.  Chem.  Soc., 
1882,  Abs.  535. 


354  MIDRIA  TIC  ALKALOIDS. 

ing  the  separator  in  warm  water).  Also  small  additions  of  alco- 
hol, or  of  fresh  chloroform  and  of  water,  may  be  made  by  turn- 
ing rather  than  by  shaking  the  separator.  And  a  shallow  dividing 
layer  of  persistent  emulsion  may  be  managed  by  transferring  it 
to  a  test-tube  for  treatment  with  additional  chloroform  and  water, 
or  with  a  little  alcohol.  The  united  portions  of  watery  solution, 
filtered  if  not  entirely  clear,  are  now  made  distinctly  alkaline  by 
adding  ammonia,  and  shaken  out  with  two  or  three  portions  of 
chloroform,  which  is  drawn  off  clear.  Films  of  emulsion  may  be 
washed  with  chloroform  on  a  filter  previously  wet  with  this  sol- 
vent. The  clear  chloroformic  solution  is  evaporated  in  a  tared 
beaker  for  weight.  The  residue  may  be  purified  by  dissolving 
in  absolute  alcohol  (by  which  sulphates  are  left  behind  with  traces 
of  other  impurities),  filtering  and  washing  with  the  same  solvent, 
and  evaporating  the  filtrate  to  dryness.  Or  the  residue  from 
evaporation  of  the  chloroform  ^lay  be  purified  (according  to 
DUNSTAN  and  R.)  by  dissolving  in  hydrochloric  acidulated  water, 
filtering  and  washing,  precipitating  with  iodine  in  potassium 
iodide,  collecting  the  precipitate,  shaking  it  with  sodium  thiosul- 
phate  solution  to  liberate  the  alkaloid,  then  shaking  out  with 
portions  of  chloroform  as  before.  In  the  above  process  the  aci- 
dulous water  solution  may  be  washed  with  petroleum  benzin 
with  advantage,  unless  the  constituents  in  aqueous  solution  are 
such  as  to  form  a  troublesome  emulsion  with  the  benzin. 

In  separation  from  animal  tissues  and  other  matters  under  an 
analysis  for  poisons,*  the  finely  divided  material  is  to  be  di- 
gested, with  the  addition  (if  need  be)  of  water  enough  nearly  to 
cover  the  solids  and  dilute  sulphuric  acid  to  strong  acidulation, 
for  an  hour  or  two,  at  about  70°  C.  The  mixture  is  now  filtered 
by  a  filter-pump,  or  strained,  and  the  residue  digested  some  time 
with  two  successive  smaller  portions  of  slightly  acidulated  water, 
each  portion  being  filtered  or  strained  into  the  first  filtrate,  the 
filters  being  sparingly  washed  with  slightly  acidulated  water. 
To  the  liquid  is  now  added  enough  calcined  magnesia  to  neutral- 
ize the  excess  of  acid,  still  leaving  a  distinctly  acid  reaction,  and 
the  whole  is  concentrated  on  the  water- bath  to  a  thin  syrupy  con- 
sistence, stirring  to  promote  evaporation  and  prevent  any  drying 
at  the  edges.  The  mixture  is  now  drained  into  a  flask  ;  the  dish 
is  moistened  with  water  and  then  rinsed  with  repeated  small 
portions  of  alcohol  into  the  flask,  each  alcoholic  addition  being 
mixed  by  gentle  agitation  of  the  flask,  and  alcohol  further  added 

1  Farther  see  DRAGENDORFF:  "Gerichtl.  Cheraie."  BLYTH:  "  Poisons,"  p. 
346  (New  York  edition).  WHAKTON  and  STILLE,  4th  ed.,  1884  (Amory  and 
Wood),  p.  425.  WORM  LEY:  "  Poisons,"  3d  ed.,  1885,  p.  645. 


AT RO  PINE.  355 

to  make  in  all  about  3  or  4  volumes  to  1  volume  of  the  syrupy 
liquid.  A  few  drops  of  dilute  sulphuric  acid  are  added,  the 
whole  is  well  shaken  and  set  aside  for  some  hours,  then  filtered, 
the  filter  washed  with  alcohol,  and  the  filtrate  evaporated  in  a 
flask  to  remove  all  the  alcohol.  The  watery  solution,  if  it  be 
not  thin  and  limpid,  is 'diluted  with  only  enough  water  to  ob- 
tain this  consistence.  The  acidulous  liquid  is  now  shaken  out 
with  one  or  more  portions  of  petroleum  benzin,  or  of  benzene, 
or  of  both,  repeating  (if  the  layers  separate  well)  as  long  as  the 
solvent  removes  organic  matters,  and  lastly  the  liquid  is  well 
shaken  out  with  chloroform.  The  benzin  and  benzene  solutions 
may  be  examined,  if  desired,  for  other  substances  :  the  chloroform 
solution  is  washed  with  a  little  water  to  which  a  drop  of  diluted 
sulphuric  acid  is  added,  and  this  aqueous  solution  is  added  to  the 
liquid  under  analysis.  This  liquid  is  now  made  alkaline  by  add- 
ing ammonia,  and  shaken  out  with  two  or  three  portions  of 
chloroform.  The  chloroformic  solution  is  evaporated  to  dryness 
in  a  beaker  or  assay-flask.  The  residue  is  dissolved  by  warm  ab- 
solute alcohol,  in  repeated  small  portions,  the  alcoholic  solution 
filtered  through  a  small  filter  into  a  small  foot-glass  graduated 
in  c.c.,  the  filter  being  washed  several  times  with  a  little  of  the 
alcohol.  Of  the  mixed  filtrate  ^  by  volume  is  evaporated  to 
dryness  in  a  tared  beaker,  for  weight :  the  ^  is  evaporated  in 
one  or  more  small  porcelain  evaporating  dishes,  for  Vitali's  test, 
taking  first  two  or  three  drops  by  a  pipette  to  evaporate  in  the 
dish,  then  repeating  the  evaporation  on  the  same  spot  until  a 
concentrated  residue  is  obtained.  If  this  test  does  not  reveal 
atropine,  one  edge  of  the  residue  in  the  beaker  is  carefully  sub- 
jected to  the  same  test,  after  which  the  remains  of  the  test  are 
fully  wiped  out  with  filter- paper,  noting  what  fraction  of  the 
entire  residue  appears  to  have  been  removed.  Whatever  the  result 
of  this  test  upon  either  residue,  the  entire  (remaining)  residue 
in  the  beaker  is  now  dissolved  in  a  small,  measured  .volume  of 
water.  The  solution  is  subjected  to  the  physiological  test,  which 
may  be  made  quantitative,  and  to  the  bromine  test,  and  other 
precipitations,  working  with  drop  portions  on  a  glass  slide,  over 
white  or  black  ground,  using  a  magnifier,  comparing  crystals 
under  the  microscope  with  those  of  a  known  solution  of  atro- 
pine.— It  must  be  ascertained  that  none  of  the  solvents  gives  any 
residue  by  evaporation. 

From  the  urine  atropine  may  be  separated  by  acidulating 
with  sulphuric  acid,  washing  with  chloroform,  making  alkaline  by 
ammonia,  shaking  out  with  chloroform,  and  proceeding  from  this 
point  as  above  directed  in  treatment  of  the  alkaline  aqueous  liquid. 


356  MIDRIA  TIC  ALKALOIDS. 

Atropine  lias  been  recovered  from  tissues  after  2|  months' 
putrefaction  (DRAGENDORFF). 

f. — Quantitative. — Pure  atropine  is  dried  at  or  below  100°  C. 
and  weighed  as  anhydrous  alkaloid.  In  ordinary  methods  of  sep- 
aration the  isomers  hyoscyamine  and  hyoscine,  so  far  as  present 
in  the  material,  will  be  included  in  the  estimation,  affording  a 
statement  of  total  (midriatic)  alkaloid,  as  atropine.  For  certainty 
of  the  absence  of  non-alkaloidal  matter  the  separation  from  the 
periodide  precipitate  is  a  resource  (p.  354).  The  crystalline  (or 
amorphous)  residue  by  evaporation  of  a  chloroformic  solution 
prepared  with  the  precautions  already  given  is  clean  and  suitable 
for  gravimetric  estimation. 

In  a  physiological  valuation,  taking  Dr.  Squibb's  results  with 
atropine  sulphate  (p.  345)  as  a  basis,  1  part  of  atropine  sulphate  in 
about  90000  parts  of  aqueous  solution,  or  1  part  of  free  atropine 
in  about  106000  parts  of  aqueous  solution,  by  application  of  one 
drop  of  such  solution  to  the  human  eye,  should  cause  a  percepti- 
ble difference  of  dilatation  of  the  pupil  within  one  hour.  For 
convenience  of  making  the  solution,  0.010  gram  of  the  alkaloidal 
material  to  be  tested  may  be  dissolved  to  make  10.6  c.c.  (for  free 
alkaloid),  or  9.0  c.c.  (for  sulphate),  and  then  10  c.c.  of  either  of 
these  solutions  is  to  be  diluted  to  1000  c.c.  A  single  full  drop 
is  let  fall  from  a  dropping  tube  directly  into  the  eye  while  the 
lids  are  held  open  and  the  head  thrown  back,  this  position  being 
maintained  without  winking  for  half  a  minute  after  the  drop  is 
introduced.  The  trial  may  be  repeated  on  the  same  individual 
and  on  different  individuals.  If  dilatation  be  not  obtained  a 
stronger  solution  is  to  be  tried,  and  trials  repeated  until  the  limit 
of  strength  for  dilatation  is  obtained  (p.  346). 

Precipitation  of  atropine  by  Mayer's  solution  of  potassium 
mercuric  iodide  is  not  very  close,  but  has  been  used  by  DKA- 
GENDORFF1  both  in  the  gravimetric  and  volumetric  way.  In  the 
final  volumetric  estimation  the  dilution  is  to  be  made  such  that 
there  shall  be  1  part  of  alkaloid  in  350  to  500  parts  of  solution ; 
the  reagent  diluted  to  one-half  Mayer's  strength ;  and  an  addition 
is  directed  of  0.00005  gram  of  alkaloid  for  each  c.c.  of  total 
liquid.  The  reagent  is  to  be  added  very  slowly,  so  that  the  pre- 
cipitate shall  crystallize  and  be  able  to  subside.  In  the  volume- 
tric way  the  end  reaction  is  found  by  filtering  from  time  to  time 
a  few  drops  through  a  very  small  filter,  and  adding  to  this  fil- 
trate a  drop  of  the  reagent,  then  returning  this  portion  to  the 

1  "  Werthbestiinmung,"  1874;  "Plant  Analysis,"  1882  (London,  1884). 


ATROPINE.  357 

entire  liquid,  into  which  the  little  filter  is  rinsed  with  a  few 
drops  of  water.  Each  c.c.  of  Mayer's  (full  strength)  solution 
denotes  0.0125  gram  of  alkaloid  as  atropine  (Dragendorff's  ex- 
periments).1 

In  the  gravimetric  estimation  by  potassium  mercuric  iodide, 
Dragendorff  directs  precipitation  of  an  acidulated  solution  of  the 
alkaloid,  1  to  350  or  ±00,  with  excess  of  Mayer's  solution.  After 
standing  24  hours  the  precipitate  is  collected  on  a  small  filter  and 
drained,  washed  \ntli  distilled  water,  dissolved  in  alcohol  of  90 
to  95$,  and  the  alcoholic  solution  and  washings  are  evaporated  in 
a  beaker  and  the  residue  dried  at  100°  C.  Of  the  weight  of  the 
residue  44.9$  is  atropine.  The  results  are  not  very  close,  and 
will  vary  with  the  extent  of  water-washing  of  the  precipitate. 

g. — Tests  of  purity. — Atropine  and  its  salts,  when  heated 
over  the  flame,  should  vaporize  without  residue.  It  should  not 
have  a  yellowish  tint,  and  when  treated  with  concentrated  sul- 
phuric acid,  or  with  excess  of  ammonia,  should  not  be  colored. 
One  drop  of  a  solution  in  1000  parts  of  water,  on  the  tongue, 
should  cause  a  bitter  and  acrid  taste.  One  drop  of  a  solution  in 
45000  parts  of  water,  placed  in  the  human  eye,  should  cause  di- 
latation in  about  45  (not  less  than  60)  minutes.  Free  atropine 
and  its  salts  should  correspond  to  the  solubilities  stated  under  c. 
If  0.001  be  dissolved  in  1  c.c.  of  water,  and  a  drop  of  gold  chlo- 
ride solution  be  added,  a  lustreless  golden  precipitate  should  be 
obtained.  Further  in  distinction  from  hyoscyamine  and  hyos- 
cine,  note  the  reactions  with  gold  chloride,  and  the  results  by 
saponification,  pp.  343,  349. 

Prof.  E.  SCHMIDT  (1884)  proposes  that  there  should  be  only 
two  commercial  names  of  the  midriatic  alkaloids,  namely :  atro- 
pine, with  a  melting  point  of  115°  to  115.5°  C.  (239°-240°  F.) 
(compare  p.  345) ;  and  hyoscyamine,  with  a  melting  point  of 
108.5°  C.  (227. 5°  F.) 

1  Only  empirical  data  can  be  used.  And  whether  this  factor  of  Dragen- 
dorff  be  adopted,  or  one  obtained  with  a  solution  of  atropine,  the  concentration 
and  other  conditions  must  be  held  uniform.  Before  the  addition  of  Mayer's 
solution  ceases  to  increase  the  precipitate,  a  condition  of  equilibrium  is  reached, 
in  which  an  addition  of  a  solution  of  atropine  salt  also  causes  a  precipitate. 
GATHER  (Zeitsch.  anal.  Chem.,  8,  477)  gave  to  1  c.c.  of  Mayer's  solution  the 
value  of  0.0193;  and  Mr.  Mayer  himself,  on  obscure  theoretical  grounds,  put 
the  value  at  0.0145.  The  latter  figure  corresponds  to  the  ratio  of  1  atom  of 
mercury  to  1  molecule  of  atropine — CnEUsNOsCHl^Hgla.  But  the  gravimetric 
indications  of  Dragendorff,  given  in  the  next  paragraph  of  the  text,  correspond  to 
the  ratio  of  2  atoms  of  mercury  to  1  molecule  of  atropine — (CiTHasNOsHIjaHgla. 
Further  upon  this  reaction  see  the  author's  contribution  on  "Estimation  of  Al- 
kaloids by  Potassium  Mercuric  Iodide,"  1880:  Am.  Chem.  Jour.,  2,294-304, 
at  pp.  208-300;  Chem.  News,  45,  114-115;  Ber.  d.  chem.  Ges.,  14,  1421. 


358  OPIUM  ALKALOIDS. 

MINERAL  OILS,  SEPARATION  OF.     See  FATS  AND 

OILS,  p.  274. 

MORPHINE.     See  OPIUM  ALKALOIDS,  p.  362. 

MYRISTIC  ACID.     See  p.  245. 

NARCEINE.     NARCOTINE.     See  OPIUM  ALKALOIDS. 

OAK  BARK  TANNIN.     See  TANNINS. 

OLEIC  ACID.     See  p.  246. 

OLEOMARGARIN.     See  p.  292. 

OLIVE  OIL.     See  p.  285. 

OPIUM  ALKALOIDS.— Alkaloids  in  the  concrete,  milky 
exudation  obtained  by  incising  the  unripe  capsules  of  Papaver 
somniferum. 

List  of  Alkaloids,  with  description  of  those  of  minor  importance. 

Chemical  Constitution.     Grouping  by  color  tests. 

Classification  by  deportment  with  sulphuric  acid. 

MORPHINK  :  Yield  in  opium ;  analytical  outline ;  crystallization  and  heat  reac- 
tions of  the  alkaloid  and  its  salts  (a);  physiological  effects  (5);  solubili- 
ties of  the  alkaloid  and  its  salts  (c);  color  tests  and  limits  of  each,  precipi- 
tations (d)-,  separations  in  general,  from  tissues  in  cases  of  poisoning,  with 
limits  of  recovery  and  organs  of  deposition  (e);  estimation,  gravimetric  and 
volumetric,  in  opium  by  the  several  pharmacopceial  and  other  methods, 
and  in  tincture  of  opium,  with  authorized  standards  (/);  impurities  by  the 
pharmacopoeia!  standards  in  different  countries  (g). 

Narcotine :  analytical  outline,  constants,  and  directions  for  analysis. 

Codeine :  description  and  analysis ;  tests  for  purity. 

Apomorphine  :  description;  tests;  impurities. 

(1)  Morphine,  C17H19NO3.     SERTURNER,  1816.     See  p.  362. 

(2)  Codeine,     C18H21NO3.     KOBIQUET,  1832.     See  p.  388. 

(3)  Thebame,  C19H21NO3.     THIBOUMERY,  1835.     Yield,  0.15- 

1.0$.  Needles  or  quadratic  plates.  Of  sharp  and  styptic  taste, 
and  tetanic  poisonous  effect,  fatal  in  doses  smaller  than  those 
of  morphine.  Soluble  in  140  parts  ether,  soluble  in  benzene, 
amyl  alcohol,  and  in  chloroform,  not  in  petroleum  benzin. 
Of  alkaline  reaction,  and  neutralizes  acids.  Colored  by  sul- 

fhuric  acid,  blood-red  turning  yellow  ;  according  to  HESSE 
1872)  green  to  brown-green  ;  by  Froehde's  reagent,  orange  ; 
by  nitric  acid,  yellow.     By  boiling  dilute  acids,  converted 


OPIUM  ALKALOIDS.  359 

into  Thebenine,  which  is  changed  by  concentrated  acid  to 
Thebaioine,  both  these  products  being  isomers  of  thebaine, 
and  amorphous. 

<4)  Narcotine,  C22H23NO7.     DESRONE,  1803.     See  p.  387. 

($)  Narceine,  C23H29NO9.  PELLETIEK,  1832.  Yield,  0.02  to 
0.1$.  Crystallizable,  in  four-sided  prisms  or  in  needles.  Of 
bitter  taste,  styptic  after- taste,  and  purely  hypnotic  effect. 
Sparingly  soluble  in  hot  water  or  cold  alcohol,  soluble  in  hot 
alcohol ;  nearly  insoluble  in  ether,  or  benzene,  or  petroleum 
benzin,  or  (WORMLEY)  in  chloroform  ;  moderately  soluble  in 
amyl  alcohol,  not  from  acid  solutions.  It  is  of  neutral  re- 
action, but  unites  with  acids,  forming  crystallizable  salts. 
Colored  by  sulphuric  acid,  brown  or  black  to  yellow  or  red ; 
by  nitric  acid,  yellow ;  by  Froehde's  reagent,  yellow-brown 
to  blue. 

(6)  Pseudomorphine,  C17H19NO4 .     PELLETIEK  and  THIBOUMERY, 

1835.  Yield,  not  over  0.02  per  cent.  Lustrous  crystals. 
Tasteless,  and  of  neutral  reaction.  Insoluble  in  water,  alco- 
hol, ether,  chloroform,  dilute  acids,  or  alkali  carbonates; 
soluble  in  caustic  alkalies  or  lime  solution.  Colored  by  sul- 
phuric acid  an  olive  green ;  by  nitric  acid,  orange-red. 
Forms  acidulous  crystallizable  salts,  difficultly  soluble  in 
water  or  alcohol.  HESSE  infers  that  this  is  the  same  as  Oxy- 
morphine,  formed  by  action  of  nitrites  on  morphine,  as 
stated  under  Morphine,  d. 

(7)  Papaverine,  C21H21NO4.     MERCK,  1848.     Yield,  sometimes 

as  high  as  1  per  cent.  Crystalline,  in  white  needles  or 
prisms.  In  action  resembles  morphine,  but  is  much  feebler. 
It  is  slightly  soluble  in  cold  alcohol  and  in  ether,  freely  in 
hot  alcohol,  moderately  soluble  in  amyl  alcohol,  in  benzene, 
and  in  petroleum  benzin,  soluble  in  chloroform  both  from 
alkaline  and  from  acid  solutions.  Does  not  neutralize  even 
acetic  acid.  Its  salts  are  very  difficultly  soluble  in  water ; 
its  sulphate  dissolves  in  sulphuric  acid,  but  is  precipitated 
on  adding  water.  Colored  by  concentrated  sulphuric  acid 
deep  blue-violet,  soon  fading ;  Froehde's  reagent,  violet  to 
blue ;  sulphuric  acid,  with  permanganate  added,  green 
turning  to  gray.  Dilute  solution  not  precipitated  by  phos- 
phomolybdate. 

(8)  Codamine,   C20H25NO4.     HESSE,  1872.      Forms   hexagonal 

prisms,  ban  be  sublimed ;  melts  at  121°  C.  Soluble  in 
tot  water,  in  alcohol,  ether,  chloroform,  benzene.  Sulphuric 
acid  with  a  little  ferric  salt  colors  it  green-blue,  at  100°  C. 
dark  violet. 


360  OPIUM  ALKALOIDS. 

(9)  Laudanine,  C20H25NO4.     HESSE,  18TO.     Crystallizes  in  fine 

prisms,  sparingly  soluble  in  alcohol  or  ether,  soluble  in 
chloroform  or  benzene.  Sulphuric  acid  containing  ferric 
salt  colors  it  rose-red,  at  150°  C.  violet-red.  In  physiologi- 
cal effect,  like  thebaine,  a  tetanic  poison,  more  active  than 
morphine,  less  active  than  thebaine. 

(10)  Laudanosine,  C21H27NO4.      HESSE,  1871.     Crystallizable. 
A  tetanic  poison  to  animals.     Soluble  in  ether,  chloroform, 
benzene,  and  in  alcohol,  insoluble  in  water. 

(11)  Meconidine,  C21H23]$rO4  -     HESSE,  1870.    Amorphous.    Fu- 
sible at  58°  C.,  instable.     Soluble  in  alcohol,  ether,  chloro- 
form, benzene.      Colored  red  and  decomposed  by  mineral 
acids.     Alkaline  in  reaction. 

(12)  Lanthopine,  C23H25]SrO4.      HESSE,  1870.      Minutely  crys- 
talline.    Slightly  soluble  in  alcohol,  ether,  or  benzene,  freely 
soluble   in   chloroform.     Does  not  neutralize   acids.     Sul- 
phuric acid  with  ferric  salt  does  not  color  it. 

(13)  Protopine,    C20H19NO5.       HESSE,     1871.      Crystallizable. 
Insoluble  in  water,  freely  soluble  in  ether,  sparingly  solu- 
ble in  alcohol,  chloroform,  or  benzene.     Colored  dark  violet 
by  sulphuric  acid  with  ferric  salt. 

(14)  Cryptopine,  C21H23KO5.     T.  and  H.  SMITH,  1864.     Yield 
very  minute.     Hexagonal  crystals.     A  bitter  taste  and  pun- 
gent, cooling  after-taste.     Hypnotic  and  midriatic.     Insolu- 
ble in  water,  ether,  or  benzene ;  soluble  in  hot  alcohol  or 
chloroform.     A  strong   base.     Colored  by  sulphuric  acid, 
blue  ;  on  adding  potassium  nitrate,  green. 

(15)  Gnoscopine,  C^HgeNgOj^.     T.   and  H.   SMITH,   1878.     In 
long  needles.     Slightly  soluble  in  cold  alcohol,  freely  solu- 
ble in  benzene,  chloroform,  or  carbon  disulphide.     Combines 
with  acids.     Colored  yellow  by  sulphuric  acid,  turning  red 
on  addition  of  nitric  acid. 

(16)  Rhoeadine,  C21H21NOfl.     HESSE,  1865.     Also  in  Papaver 
Rhoeas.     Crystallizable.     Not  poisonous.     Scarcely  soluble 
in  water,  alcohol,  ether,  chloroform,  or  benzene.     Feebly 
alkaline.     Does  not  form  definite  salts.     Mineral  acids  dis- 
solve  it   with   a   red   color,    and  with   the   production   of 
jRhoeagenin,  isomeric  with  rhoeadine,  a  strong  base,  neu- 
tralizing acids.     Rhoeadiue  is  colored  olive-green  by  sul- 
phuric acid,  yellow  by  nitric  acid. 

(17)  Hydrocotarnine,  C12H15NO?.     HESSE,  1871.    A  constituent 
of    opium  ;    also    produced    from    narcotine.       Cotarnine 
(C12H13NO3)  is  first  formed  by  oxidation  of  narcotine,  then 
reduced  to  hydrocotarnine  (0.  R.  A.  WRIGHT,   1877  and 


OPIUM  ALKALOIDS.  361 

earlier).  In  monoclinic  prisms.  Poisonous.  Soluble  in 
alcohol,  ether,  chloroform,  and  in  benzene.  Slightly  va- 
porizable.  Colors  yellow  in  cold  sulphuric  acid,  red  on 
heating. 

^Numerous  derivatives  of  the  natural  alkaloids  of  opium 
are  known.  A  description  of  one  of  these,  Apomorphine, 
C17H17NO2,  is  given  at  the  close  of  this  article. 

Constitution  of  Opium  alkaloids.1  —  Morphine  and  codeine 
are  closely  related  to  each  other  and  to  artificial  derivatives  of 
each.  Narcotine  and  narceine  also  are  chemically  allied,  with 
cotarnine  and  hydrocotarnine  as  derivatives.  The  relation  of 
both  these  groups  to  pyridine,  the  type  of  alkaloids,  has  been 
shown  by  v.  Gerichten.  The  immediate  structure  of  morphine 
and  codeine  is  as  follows  : 


Morphine,  C17H17NQ  j  ^     Codeine,  C17H17NO  j 

The  structure  of  narceine  and  narcotine  : 

(C02H 

Narceine,  (C13H20NO4)  -  CO  -  C6H2  1  OCH3 

(  OCH3 

(COH 

Narcotine,  (Gj^^CR^O^  -  CO  -  C6H2  1  OCH3 

(  OCH3 

Codeine,  therefore,  is  morphine  mono-methyl  ether.  The 
corresponding  morphine  mono-ethyl  ether  is  readily  formed. 

And  morphine  is  artificially  converted  into  codeine  (GRi- 
MAUX,  1881)  by  treatment,  successively,  with  methyl  iodide  and 
fixed  alkali.  Hydrocotarnine  is  not  only  found  with  narcotine^ 
in  opium,  but  is  producible  from  narcotine  by  chemical  treat- 
ment. 

Among  the  products  of  decomposition  of  narcotine  are  me- 
conin,  opianic  acid,  and  hemepicacid  —  non-nitrogenous  bodies,  of 
which  the  first-named  is  found  ready  formed  in  opium.  These 

'C.  R.  A.  WRIGHT  and  co-workers,  1872-1877:  Proc.  Roy.  Soc..  20;  Jour. 
Ghem.  Soc.,  25  to  32;  on  narcotine  and  narceine,  29,  461;  28,  573;  32,  525; 
on  morphine  and  codeine,  25,  150,  504.  0.  HESSE,  1872:  Ann.  Ghem.  Phar., 
Suppl.  Bd.,  8,  261;  Jour.  Chem.  Soc.,  25,  721;  1884:  Liebig's  Annalen,  222, 
203;  Jour.  Chem.  Soc.,  46.  613.  E.  v.  GERICHTEN,  1881-83:  Ber.  d.  chem.  Oes., 
13,  1635;  14,  310;  15,  2179;  Jour.  Chem.  S»c.,  40,  110,  445;  44,  221.  GRI- 
MAUX,  1881-83:  Ann.  Chim.  Phys.  [5]  27,  273;  Jour.  Chem,.  Soc.,  44,  358. 
CHASTAING,  1881:  Compt.  rend.,  94,  44;  Jour.  Chem.  S»c.,  42,  413.  A  list  of 
opium  alkaloids,  with  a  few  derivatives,  arranged  in  order  of  the  number  of  car- 
bon atoms,  is  given  in  the  Pharmacographia  of  F.  &  H.,  2d  ed.,  p.  59. 


362  OPIUM  ALKALOIDS. 

three  bodies  are  related  in  structure,  as  benzene  derivatives,  as 
follows  : 

(  (OCH3)2  (  (OCH3)2 

C6H2  \  COoH         C6H2  \  CO-H 
|  COH  (  C02H 

Opianic  acid.  Hemepinic  acid. 

Hesse  (1872)  presented  a  practical  division  of  the  opium  al- 
kaloids into  groups,  according  to  their  deportment  with  pure 
sulphuric  acid,  as  follows  : 

1.  a.  —  Dirty  dark-green.  —  Morphine,  pseudomorphine,  codeine. 
J  —  Dirty  red-  violet.  —  Laudanine,  codamine,  laudanosine. 

2.  —  Dirty  green  to  brown-green.  —  Thebaine  [?],  cryptopine,  pro- 

topine. 

3.  a.  —  Dark-violet.  —  Papaverine. 

b.  —  Black-brown  to  dark-brown.  —  Narceine,  lanthopine. 

4.  —  Dirty  red-  violet  (of  shade  different  from  that  of  1  5). 

cotine,  hydrocotarnine. 


MORPHINE.  C^H^TTOo1  =  285.  Crystallized,  C17H19NO3  . 
H2O  =  303.  (For  structure  see  p.  361.)  —  In  opium,  as  sulphate 
and  meconate.  In  all  parts  of  the  Papaver  somniferum,  more 
particularly  in  the  leaves,  stems,  and  seeds  just  before  maturity. 
In  other  species  of  Papaver.  —  Of  dried  opium  crystallized  mor- 
phine forms  from  3  to  20  per  cent.  :  by  the  U.  S.  Ph.  (1880)  12 
to  16,  average  14,  per  cent  ;  by  the  Br.  Ph.  (1885)  10  per  cent. 
(or  9.5  to  10.5  per  cent.);  by  the  Ph.  Germ.  (1882)  at  least  10 
per  cent.  ;  by  the  Ph.  Fran.  (1884)  10  to  12  per  cent.  ;  these 
pharmacopceial  standards  being  further  defined  according  to 
methods  of  assay  given  in  each.  The  U.  S.  Ph.  of  1870  specified 
for  dried  opium  at  least  10  per  cent,  morphine  ;  the  U.  S.  Ph. 
of  1860,  for  opium  not  dried,  at  least  7  per  cent,  morphine. 
Since  1848  the  U.  S.  customs'  service  has  required  of  opium 
imported  at  least  9  per  cent,  of  morphine  on  the  moist  basis  — 
equal  to  11J-12  per  cent,  on  a  dry  basis.  And  so  well  has  the 
standard  of  importation  been  maintained  that,  for  years  before 
the  pharmacopoeia  of  1880  came  into  effect,  very  little  opium  in 
reputable  hands  in  this  country  contained  less  than  about  12  per 
cent,  of  morphine  on  a  dry  basis.  In  1882,  before  the  present 
pharmacopoeia  was  issued,  Dr.  Squibb  reported  from  230  cases 
of  opium  an  average  of  12.45  per  cent,  in  the  dry  state,  and  from 

1  LAURENT,    1847:    Ann.    Ohim.    Phys.    [3]   19,  361.        WRIGHT,   1877, 


MORPHINE.  363 

191  cases  an  average  equal  to  12.35  per  cent,  in  the  dry  state  ;  and 
in  the  same  year  Mr.  C.  "W.  Parsons  reported  the  assay  of  21  Turk- 
ish opiums  with  an  average  of  15.2  per  cent,  of  morphine  in  the 
dried  opium.  In  fact,  although  opium  was  much  stronger  than 
the  national  pharmacopoeia  required  it  to  be,  the  pharmacopoeia 
gave  no  authority  for  diluting  it.  Opium,  not  powdered,  could 
be  diluted  only  by  the  grossest  sophistication.  Additions  to 
powdered  opium,  if  made  by  reputable  persons,  were  made  in 
accordance  with  an  assay  and  then  declared  in  the  brand  of  the 
article  as  containing  a  specified  percentage  of  morphine.  If 
made  by  persons  without  repute  or  scruple,  the  limit  of  the  phar- 
macopoeia would  be  little  regarded.1 

Morphine  is  recognized  under  the  microscope  by  its  form  as 
free  alkaloid  crystallizing  from  solution  (a) ;  is  identified  by 
chemical  tests  with  ferric  chloride,  sulphuric  and  nitric  acids, 
Froehde's  reagent,  phosphomolybdate  solution,  etc.  (d.  p.  365) ; 
is  separated  by  action  of  amyl  alcohol  on  alkali  solutions,  and 
by  other  means  (e) ;  and  from  viscera,  in  cases  of  suspected 
poisoning,  and  with  reference  to  the  recovery  of  Meconic  acid, 
as  directed.  Morphine  is  usually  estimated  gravimetrically  as 
free  alkaloid  (f) ;  sometimes  volumetrically  by  Mayer's  solution 
(p.  43),  or  colorornetrically  by  iodic  acid.  The  estimation  of 
morphine  in  opium  is  indexed  under  f.  The  yield  of  mor- 
phine in  opiums  is  stated  on  p.  362.  The  tests  of  purity  of  the 
alkaloid  and  its  salts  are  given  under  g. 

a. — Morphine  crystallizes,  with  one  molecule  of  water,  in 
short,  translucent,  hexihedral  prisms  of  the  rhombic  (trimetric) 
system,  or  in  white,  lustrous  needles.  If  a  few  drops  of  a  warm 
saturated  aqueous  solution,  or  a  dilute  alcoholic  solution,  be  al- 
lowed to  evaporate  spontaneously  on  a  glass  slide,  characteristic 
crystalline  forms  are  obtained,  to  be  recognized  in  analysis  by 
comparison  with  forms  from  a  known  portion  of  morphine 
treated  in  the  same  way.  Too  rapid  evaporation  gives  an  amor- 
phous residue.  Morphine  is  permanent  in  the  air  and  below 
100°  C.,  and  becomes  anhydrous  at  120°  C.  (248°  R),  losing  5.94 
per  cent,  of  the  weight  of  the  crystals.  According  to  TAUSCH 
(1880)  the  water  is  expelled  at  100°  C.,  though  slowly.  At  150° 
C.,  in  the  "  subliming  cell "  (BLYTH,  1878),  morphine  "  clouds  the 
upper  disc  with  nebulae ;  the  nebulse  are  resolved  by  high  mag- 

1  Further,  an  article  by  the  author  "On  the  Strength  of  Opium  and  its 
Preparations  in  this  Country,  as  compared  with  the  standards  of  the  Pharma- 
copoeias of  1870  and  1880,"  1883:  Pro*  Mif.h.  State  Pharm.,  I,  48. 


364  OPIUM  ALKALOIDS. 

nifying  powers  into  minute  dots;  these  dots  gradually  get 
coarser,  and  are  generally  converted  into  crystals  at  188°  C. ;  the 
alkaloid  browns  at  or  about  200°  C."  Heated  on  platinum  foil 
the  crystals  melt,  then  char,  and  slowly  burn  completely  away. 
The  crystals  are  of  sp.  gr.  1.317-1.326  (SCHRODER,  1880).— 
Morphine  solutions  are  levorotatory  :  [a]  r  =  —  88.04  (Bou- 
CHARDAT;  HESSE,  1875). 

Crystallization  and  heat  reactions  of  Morphine  Salts. —  The 
sulphate,  (C17H19NO3)2H2SO4.5H2O  =  758,  crystallizes  easily 
in  colorless,  feathery  needles  of  silky  lustre,  permanent  in  the 
air,  losing  its  water  of  crystallization '(11. 87$)  at  130°  C.  (at  100° 
C.,  Ph.  Germ.)—  The  hydrochloride,  C17H19NO3HC1 . 3H2O  = 
375.4,  forms  colorless,  feathery  needles  of  silky  lustre,  or  minute 
white,  cubical  crystals,  permanent  in  the  air,  parting  with  the 
water  (14.38$)  at  100°  C.  (TAUSCH,  1880,  Ph.  Germ.),  at  130°  C. 
(FLUCKIGER,  "  Phar.  Chem.") — Morphine  acetate  holds  3H2O, 
with  the  molec.  weight  399,  in  a  white  or  faintly  yellowish- 
white,  crystalline  or  amorphous  powder,  slowly  losing  acetous 
vapor  in  the  air. — Morphine  hydrobromide,  with  2H2O,  crys- 
tallizes in  needles,  becoming  anhydrous  at  100°  C.  (SCHMIDT, 
1877). — Morphine  hydriodide,  2H2O,  forms  needles  and  rosettes, 
and  parts  with  its  water  at  100°  C.  (BAUEK,  1874 ;  SCHMIDT, 
1877). 

b. — Morphine  is  without  odor,  and  of  a  bitter  taste,  more 
promptly  obtained  from  its  soluble  salts.  It  is  narcotic,  hyp- 
notic, causing  contraction  of  the  pupils,  and  on  animals  often 
producing  convulsions  and  paralysis.  The  fatal  dose  is  not  at 
all  uniform  for  different  species  of  animals  of  the  same  size.  The 
alkaloid  undergoes  change,  in  part,  while  passing  through  the 
animal  body.1  Further  respecting  its  deposition  in  the  vari- 
ous organs  and  recovery  therefrom  by  analysis,  see  statements 
under  e. 

c. — Solubilities  of  the  free  alkaloid. — Morphine,  crystallized, 
is  very  slightly  soluble  in  cold  water  (1  to  5000-10000,  CHAS- 
TAING,  1882);  soluble  in  500  parts  of  boiling  water  ;  in  about  100 
parts  of  ordinary  alcohol  at  15°  C.,  or  86  parts  of  boiling  ordinary 
alcohol,  or  13  parts  of  boiling  absolute  alcohol.  The  saturated 
solution  in  cold  absolute  alcohol  contains  one  part  in  60,  and  is  not 
precipitated  by  adding  water  (Fliickiger's  "  Phar.  Chem.")  In 
different  conditions,  different  quantities  of  solvent  are  required,  as 
follows — the  "  nascent  "  condition  being  that  of  liberation  from 

1  ELusemann's  "Pflanzenstoffe,"  1883,  p.  706.    ELIASSOR,  1884. 


MORPHINE. 


365 


salt  in  aqueous  solution:  the  ether,  chloroform,  and  amyl  alcohol, 
water-washed : * 


Ether, 

Chloro- 
form. 

Amyl.  Ale. 

Benzene. 

Crystallized  

6148 

4379 

91 

8930 

Amorphous  powder 

2112 

1977 

Nascent  state. 

1062 

861 

91 

1997 

Morphine  is  not  dissolved  by  petroleum  ether.  The  solvents 
above-named,  immiscible  with  water,  do  not  take  morphine  from 
acidified  solutions.  Morphine  is  dissolved  somewhat  freely  by 
aqueous  h'xed  alkalies,  and  by  117  parts  of  water  of  ammonia  of 
sp.  gr.  0.97.  It  is  a  decided  base,  and  neutralizes  strong  acids. 

Solubilities  of  Morphine  Salts. — Morphine  sulphate  is  solu- 
ble in  23  parts  of  water  at  15.6°  C.  (DoTT,  1882) ;  in  an  average 
of  21  parts  of  water  at  15°  C.  (COBLENTZ,  1882);  in  24  parts 
water  at  15°  C.  (U.  S.  Ph.) ;  in  0.75  part  boiling  water  (U.  S.  Ph.); 
in  702  parts  of  alcohol  at  15°  C.,  or  144  parts  of  boiling  alcohol  (U. 
S.  Ph.) — Morphine  hydrocMoride  is  soluble  in  24  parts  of  water 
at  15.6°  C.  (DoTT,  1882),  or  0.5  part  of  boiling  water;  in  63  parts 
of  alcohol  at  15°  C.,  or  31  parts  of  boiling  alcohol ;  not  soluble 
in  ether  (U.  S.  Ph.) — Morphine  acetate  is  soluble  in  2^  parts  of 
water  at  15. 6°  C.  (DoTT,  method  of  digestion,  1882);  when 
freshly  prepared  in  12  parts  of  water  at  15°  C  ,  or  68  parts  of  al- 
cohol at  same  temperature  (U.  S.  Ph.)  ;  in  60  parts  of  chloroform 
(U.  S.  Ph.)  It  is  decomposed  by  boiling  alcohol,  so  that,  on 
adding  water,  free  morphine  is  precipitated  (Fliickiger,  u  Phar. 
Chem.")  Morphine  tartrate  (normal,  3H2O)  is  soluble  in  9.7 
parts  of  water  at  15.6°  C.  (!)OTT,  1882) ;  morphine  meconate 
(5H2O),  in  33.9  parts  water  at  15.6°  C.  (the same).  The  hydro- 
bromide  is  soluble,  the  hydriodide  slightly  soluble,  in  cold 
water. 

d. — The  color  tests  for  morphine,  when  the  alkaloid  is  per- 
fectly separated,  are  not  extremely  delicate,  as  compared  with 
tests  for  other  alkaloids,  and  are  more  than  usually  liable  to  error 
from  admixture  of  non-alkaloidal  matters. 

The  test  with  nitric  and  sulphuric  acids  ranks  first  as  a 
means  of  distinction.  Sulphuric  acid  itself  (strictly  free  from 


'The  author.  1875:  Am.  Chem,  6,  84;  Jour.  Chem.  Soc.,  29,  405. 


366  OPIUM  ALKALOIDS. 

nitric  acid)  does  not  color  dry  morphine  (free  from  narcotine, 
papaverine,  p.  359),  or  causes  only  the  slightest  reddish  colora- 
tion, unless  heat  be  applied.  On  the  water-bath  some  shade  of 
purple  to  brown  occurs,  later  deepening  to  a  brown.  Sulphuric 
acid  and  cane  sugar  color  morphine  purple-red.  Minute  traces  of 
nitric  acid  cause  a  violet  to  purple  color  in  the  cold  or  on  slight 
warming,  and  this  application  of  morphine  constitutes  a  very 
delicate  though  not  distinctive  test  for  nitric  acid  as  an  impurity 
in  sulphuric  acid.  Also  the  sulphuric  acid  alone  is  a  delicate  test 
for  certain  other  opium  alkaloids  as  impurities  in  morphine. 
Nitric  acid  alone  colors  morphine  red  to  orange  or  reddish-yellow 
— the  coloration  not  being  intense.  Concentrated  sulphuric  acid 
with  a  very  little  nitric  acid  gives  a  violet  color.  ERDMANN  (1861) 
employed  sulphuric  acid  with  intermixture  of  one  per  cent,  of 
nitric  acid,  sp.  gr.  1.25 — adding  8  to  20  drops  to  1  or  2  milligrams 
of  alkaloidal  solid — for  a  violet  color.  HUSEMANN  1  treated  the 
solid  alkaloidal  matter  with  a  little  sulphuric  acid,  heated  the 
solution  above  100°  C.,  but  not  as  high  as  150°  C.,  and  then 
touched  with  a  drop  or  two  of  nitric  acid  of  sp  gr.  1.2,  for  a 
dark  violet  color.  JBARFOED  (1881)  dissolves  the  solid  alkaloid  in 
concentrated  sulphuric  acid,  two  drops  for  each  milligram,  and 
heats  above  100°  C.  for  a  second  or  two,  and  then  adds,  to  a  thin 
layer  on  the  porcelain  surface,  a  minute  fragment  of  potassium 
nitrate,  a  red  color  giving  evidence  of  morphine,  a  violet-red 
obtained  with  a  good  quantity,  and  a  rose-red  when  but  a  little  is 
present.  Instead  of  nitric  acid,  other  oxidizing  agents,  potassium 
chlorate,  or  chlorine  water  may  be  used.  Of  the  forms  of  the 
test  above  mentioned  tlfe  last  given  one  is  preferred.  But  the 
test  without  heat  can  be  recommended  as  follows ; 

To  a  quantity  not  over  a  few  milligrams  of  the  dry  residue  to 
be  tested,  on  a  white  porcelain  surface,  add  a  drop  of  pure  sul- 
phuric acid,  and  rub  with  a  narrow  glass  rod  for  a  few  minutes, 
not  spreading  the  acid  more  than  is  unavoidable.  The  point  of 
the  glass  rod  is  now  touched  to  nitric  acid  of  sp.  gr.  1.42,  and 
drawn  across  the  dissolved  residue.  A  red  color,  violet  if  in- 
tense, rose  red  if  less  distinct,  and  soon  paling,  is  the  evidence  of 
morphine.  The  limit  of  quantity  revealed  with  a  good  color  by 
this  form  of  the  test  is  about  0.0005  gram  of  morphine.2  Huse- 
mann  gave,  as  the  extreme  limit,  with  heat,  0.00001  gram. 

!  1863-1876:  Arch.  d.  Pfiar.,  206,  231:  Zeilsch.  anal.  Chem.,  15,  103. 

2  "  Control  Analyses  and  Limits  of  Recovery,"  by  the  author,  1885:  Proc. 
Am.  Assoc.  Adyanc.  Sci.,  34,  111  ;  Chem.  News,  53,  78,  et  seq.  Respecting 
the  color  reactions  of  nitric  acid,  see  further  a  note  by  the  author,  1876:  Am. 
Jour.  Phar.,  48,  62. 


MORPHINE.  367 

Without  heat  there  is  less  danger  of  error  due  to  extraneous 
matters. 

Froehde's  reagent — 0.001  gram  of  molybdic  acid  or  mo- 

lybdate  of  soda  freshly  dissolved  by  aid  of  heat  in  1  c.c.  of  con- 
centrated sulphuric  acid  (Dragendorff),  and  the  solution  cooled — 
gives  a  bright  color  reaction  for  morphine,  quite  delicate,  but  not 
very  distinctive.  A  drop  of  the  reagent  is  applied  to  the  dry 
alkaloidal  residue,  not  over  a  few  milligrams,  on  a  white  porce- 
lain surface.  Morphine  gives  a  blue  color,  simply  that  of  a  cer- 
tain lower  oxide  of  molybdenum,  obtained  by  deoxidation — violet- 
blue  when  pale,  and  changing,  through  shades  of  greenish-blue, 
finally  to  dark  blue.1  Kauzmann  placed  the  limit  of  quantity  of 
morphine  responding  to  this  test  at  0.00005  gram  ;  Wormley,  for 
blue  color,  at  0.00007  gram.  Unless  other  reducing  agents  can 
be  excluded  it  is  unsafe  to  depend  upon  this  test  alone  as  evi- 
dence for  morphine. 

The  iodic  acid  test  is  another  application  of  the  reducing 
power  of  morphine,  which  promptly  liberates  iodine  from  iodic 
acid,  and  in  presence  of  starch  gives  the  blue  color  of  iodized 
starch.  It  is  generally  applied  to  the  aqueous  solution  of  a  salt 
of  morphine,  a  single  drop  of  which  is  enough.  DUPRE  (1863) 
directs  to  evaporate  the  morphine  with  a  drop  of  starch  solution 
to  dryness,  and  when  cold  to  moisten  with  a  solution  of  iodic 
acid.  WORMLEY  states  that  0.00007  gram  of  the  alkaloid  will 
give  a  blue  color.  With  very  dilute  solutions  in  considerable 
quantities,  liberated  iodine  may  be  sought  for  by  shaking,  in  a 
test-tube,  with  carbon  disulphide  or  chloroform.  The  reaction 
has  been  used  for  a  volumetric  method  of  estimation.  This  test, 
carefully  applied,  is  scarcely  exceeded  in  delicacy  by  any  other, 
and  it  furnishes  a  confirmation  to  affirmative  results  by  other 
tests,  but  the  presence  of  morphine  should  never  be  declared  upon 
the  evidence  of  this  test  alone.  The  chemist  should  clearly 
understand  that  a  multitude  of  reducing  agents,  inorganic  and 
organic,  will  liberate  iodine  from  iodic  acid. 

The  two  tests  last  above  given  depend  upon  the  reducing 
power  of  morphine.  Compared  with  other  non-volatile  natural 
alkaloids,  it  is  a  strong  deoxidizing  agent.  To  give  these  two 
tests  any  value,  non-alkaloidal  reducing  agents,  such  as  tissue 
substances,  must  be  strictly  removed.  In  any  doubt  as  to  their 
removal,  a  control  analysis  may  be  instituted,  in  which  like  tis- 

'FROEHDE,  1866;  ALM&N,  186b;  KAUZMANN,  1869;  NEUBAUER,  1870;  DRA- 
GKNDORFF,  1872.  "  Note  on  Froehde's  Reagent  as  a  test  for  Morphia,"  the  au- 
thor, 1876:  Am.  Jour.  Phar.,  48,  59.  WORMLEY  directs  a  3  per  cent,  solution 
of  molybdic  acid  in  sulphuric  acid;  BUCKINGHAM,  a  7  per  cent,  solution. 


368  OPIUM  ALKALOIDS. 

sues  or  other  matters  are  treated  with  the  same  solvents  in  the 
same  conditions,  and  the  product  subjected  to  these  final  color 
tests,  in  comparison  with  the  residues  liable  to  contain  mor- 
phine.— The  capacity  of  morphine  for  combination  with  oxygen 
renders  the  alkaloid  somewhat  instable,  though  in  other  respects 
it  is  a  quite  stable  alkaloid.  Among  the  oxidation  products  known 
are  Oxymorphine,  C17H19NO4  (perhaps  Pseudomorphine,  HESSE), 
and  Oxydimorphine,  C34H36N2O6,  formed  by  action  of  silver 
nitrite,  potassium  permanganate,  or  ferricyanide ;  and  a  body  of 
the  composition  C10H91N~O9  (CHASTAING,  1882).  By  hot  sul- 
phuric acid,  at  150°-160°  C.,  "  Sulphomorphid?  C34H36K2O8S,  is 
formed,  a  body  probably  closely  related  to  Apomorphine  sulphate. 
As  obtained  it  is  a  white,  amorphous  mass.  Nitric  acid  converts 
morphine  into  a  resinous  body,  which,  treated  with  potash,  yields 
methylamine  ( ANDERSON)  .  Gold  and  silver  are  reduced  from  so- 
lutions of  their  salts  by  morphine. 

Another  application  of  the  reducing  power  of  morphine  has 
been  made  in  a  test  by  a  drop  of  ferric  chloride  followed  by  a 
drop  of  very  dilute  solution  of  potassium  ferricyanide,  when  a 
blue  color  results  from  the  formation  of  ferrous  salt.  It  is  said 
that  a  solution  of  morphine  salt  in  10000  parts  of  water  gives  a 
blue  color  by  this  operation.  According  to  WOKMLEY,  narcotine 
and  brucine  give  this  reduction.  The  reaction  is  also  a  test  for 
Ptomaines  (which  see).  LONG  (1878  ')  observed  a  reaction  of  mor- 
phine with  ammonio-cupric  sulphate,  giving  a  green  color,  per- 
haps due  to  reduction.  When  morphine  is  treated  with  concen- 
trated sulphuric  acid  (p.  365),  and  then  with  potassium  chromate, 
a  green  color  is  obtained,  due  to  the  reduction  of  the  chromium. 
Therefore,  in  the  fading  purple  test  for  strychnine,  morphine,  if 
present  in  sufficient  quantity,  gives  a  green  color  (not  fading). 

Ferric  chloride,  as  a  normal  salt,  with  no  free  hydrochloric 
acid,  in  solution  of  ordinary  reagent  strength,  gives  a  blue  color 
with  morphine  or  its  salts.  The  solid  residue,  while  cold,  on  a 
white  porcelain  surface,  is  moistened  with  a  drop  of  the  reagent, 
or  by  touching  with  a  narrow  glass  rod  wet  with  the  reagent. 
According  to  WOEMLEY,  a  good  deep  color  can  be  obtained  with 
0.0007  gram  (0.001  grain)  of  alkaloid  in  solid  residue.  A  solu- 
tion of  morphine  must  be  as  concentrated  as  1  :  600  in  order  to 
give  the  color.  Less  delicate  than  the  tests  previously  given, 
this  test  is  quite  as  characteristic  as  any  other.u  It  is  necessary, 

1  Chem.  News,  38 ;  Am.  Jour.  Phar. ,  50,  490. 

2  A  comparison  of  the  tests  by  iodic  acid.  Froehde's  reagent,  and  ferric 
chloride,  applied  to  morphine,  grape-juice,  orange-juice,  and  saliva,  was  reported 
byD.  BROWN,  1878:  Phar.  Jour.  Trans.  [3]  8,  70;  Proc.  Am.  Pharm. ,  27,  485. 


MORPHINE.  369 

however,  to  exclude  various  organic  acids  of  aromatic  composi- 
tion, including  the  tannins,  phenols,  salicylic  acid,  etc.,  as  enu- 
merated under  Phenol,  d  1  According  to  SELMI  (1876)  certain 
cadaver  alkaloids  give  the  blue  color  to  ferric  salts,  as  well  as 
reduce  iodic  acid.  But  these  cadaveric  alkaloids  did  not  give  the 
violet  color  obtained  by  morphine  on  treatment  with  a  solution 
of  lead  dioxide  in  glacial  acetic  acid,  evaporating  at  a  gentle  heat. 

The  general  qualitative  reagents  for  alkaloids  all  respond  to 
morphine.  Phosphomolybdate  gives  a  very  nearly  complete 
precipitate  of  a  yellowish -white  color,  dissolving  in  ammonia 
with  a  blue  color.  Potassium  mercuric  iodide,  or  Mayer's 
solution,  gives  a  less  perfect  precipitate,  not  appearing  at  all  in 
solutions  of  1  to  4000.  The  precipitate  approximates  to  the  com- 
position (C;7H19lSrO3HI)4(HgI2)3.2  Iodine  in  iodide  of  potas- 
sium solution  gives  a  reddish-brown  precipitate,  immediately 
visible  in  one  drop  of  a  solution  of  the  alkaloid  in  10000  parts 
of  water  (WORMLEY)  ;  under  the  microscope  in  a  1  to  100000 
solution  (SELMI,  1876).  On  standing,  reddish-brown  crystals 
form.  The  precipitate  dissolves  in  alcohol,  in  alkalies,  slowly  in 
acetic  acid.  Its  distinction,  under  the  microscope,  from  other 
opium  alkaloids,  is  given  by  SELMI,  1876.  Potassium  iodide 
gives  a  formation  of  needle-shaped  crystals,  somewhat  character- 
istic, obtained  only  in  quite  concentrated  solutions. — Tannic 
acid  and  picric  acid  give  precipitates  in  solutions  not  very 
dilute. — Alkali  carbonates  and  bicarbonates  precipitate  morphine, 
not  soluble  in  excess  of  the  precipitant.  Alkali  hydrates  give  a 
crystalline  precipitate,  dissolved  by  excess  of  fixed  alkalies,  and 
by  lime  solution,  sparingly  soluble  in  excess  of  ammonia. 

Crystals  of  free  morphine,  obtained  by  precipitation  with  a 
little  excess  of  ammonia,  or  by  spontaneous  evaporation  of  a 
dilute  alcoholic  or  warm  aqueous  solution,  examined  under  the 
microscope  (in  comparison  with  known  morphine  under  like 
treatment),  give  valuable  confirmatory  evidence  of  the  identity 
of  the  alkaloid  (p.  363). 

e. — Separations. — Aqueous  solutions  of  morphine  are  con- 
centrated on  the  water-bath  without  marked  loss,  but  if  the 
concentration  require  long  time,  or  if  the  solution  be  complex, 
in  a  quantitative  separation,  it  is  better  to  evaporate  under  dimin- 
ished pressure  at  temperature  not  above  60°  to  75°  C. — From 

1  CHASTAING  (1881)  claims,  from  the  chemical  proportions  in  which  mor- 
phine unites  with  fixed  alkalies,  and  other  considerations,  that  this  alkaloid  is 
in  fact  a  phenol. 

2  The  author,  1880:  Am.  Chem.  Jour.,  2,  294. 


370  OPIUM  ALKALOIDS. 

substances  insoluble  in  acidified  water  or  alcohol  these  solvents 
remove  morphine  in  its  salts,  and  hot  alcohol  may  be  used  to  dis- 
solve out  the  free  alkaloid.  Of  solvents  not  miscible  with  water, 
amyl  alcohol  is  the  most  satisfactory  for  morphine.  The  acidified 
aqueous  solution  may  be  purified,  or  freed  from  other  alkaloids, 
by  shaking  out  with  benzene,  or  chloroform,  or  ether,  and  finally 
with  amyl  alcohol  itself.  Then  the  liquid  is  made  alkaline  by 
adding  ammonia,  and  exhausted  of  morphine  by  repeated  por- 
tions of  amyl  alcohol,  or  by  a  continuous  liquid-extraction  appa- 
ratus supplied  with  this  solvent.  It  is  to  be  remembered  that 
amyl  alcohol  carries  with  it  a  little  of  the  aqueous  solution, 
so  that  the  amyl  alcohol  solution  requires  water-washing,  and  a 
little  waste  occurs. 

In  separation  from  the  tissues  and  contents  of  the  stomach, 
or  other  matters,  in  analysis  for  poisons,1  the  solids  are  finely 
divided,  in  a  good-sized  evaporating-dish,  by  playing  upon  the 
material  with  a  pair  of  bright,  sharp  shears.  The  divided  ma- 
terial may  then  be  treated  as  directed  under  Atropine,  p.  354, 
substituting  amyl  alcohol  for  chloroform  as  a  solvent  of  morphine. 
Tartaric  acid  may  be  used  for  acidulation  instead  of  sulphuric,  to 
favor  the  rejection  of  ptomaines  (GuAREScm  and  Mosso,  1883). 
If  it  be  analysis  for  opium  constituents,  it  is  to  be  understood 
that  Narcotine  is  dissolved  sparingly  by  amyl  alcohol  applied  to 
acidulous  solutions,  also  sparingly  dissolved  by  benzene  applied 
to  alkaline  solutions,  morphine  remaining  undissolved  in  both 
these  cases.  Unless  morphine  be  found  in  more  than  traces, 
narcotine  is  not  likely  to  be  recovered  with  identification. 

Evidence  of  opium,  in  distinction  from  morphine  alone,  is 
more  confidently  sought  through  tests  for  Meconic  acid.  This 
acid  may  be  separated  from  the  aqueous  liquid,  in  the  course  for 
morphine,  if  acetic  acid  be  added  instead  of  tartaric  acid,  for 
acidulation.  The  filtered  aqueous  liquid  is  treated  with  lead 
acetate  solution,  just  sufficient  to  complete  a  precipitate  formed, 
and  filtered.  The  filtrate  is  treated  with  enough  hydrogen 
sulphide  gas  to  throw  down  all  the  lead,  then  filtered,  and  the 
filtrate  treated  in  the  course  of  analysis  for  the  morphine  The 
precipitate  first  formed  on  adding  the  lead  acetate  is  washed  on 
the  filter  with  a  little  water,  carried  through  the  filter-point  with 
a  thin  jet  of  water,  the  lead  meconate  decomposed  by  hydrogen 
sulphide  gas,  the  mixture  filtered,  the  filtrate  evaporated,  the 

1  Toxicology:  Taylor  on  Poisons;  Blyth's  Poisons;  Wharton  and  Stille. 
vol.  2,  1884;  Dragendorff's  "  Ermittelung  von  Giften"  and  "Organischer 
Gifte";  Wormley's  "  Microchemistry  of  Poisons,"  3d  edition,  1885.  STEUVE, 
1873:  Zeitsch.  anal.  Chem.,  12,  168. 


MORPHINE.  371 

residue  taken  up  with  strong  alcohol,  this  solution  filtered  and 
evaporated,  the  residue  taken  up  with  warm  water,  and  tested, 
with  ferric  chloride  and  other  reagents,  for  Meconic  acid  (which 
see). 

The  residue  from  the  careful  final  evaporation  of  the  am  vl 
alcohol  solution  of  morphine — which  may  be  divided  in  several 
dishes  for  the  tests  and  for  weight  as  directed  in  analysis  for 
atropine — is  examined  for  its  deportment  in  tests  by  (1)  sulphuric 
and  nitric  acids,  (2)  sulphuric  and  molybdic  acids,  (3)  ferric 
chloride,  (4)  iodic  acid,  and  (5)  with  phosphomolybdate,  as  direct- 
ed for  each  under  d.  Also  (6)  a  drop  of  the  warm  aqueous,  or 
dilute  alcoholic,  solution  is  allowed  to  evaporate  very  slowly, 
under  the  microscope,  for  crystals  of  free  morphine,  to  be  recog- 
nized as  stated  under  a.  Other  tests  may  be  added. 

The  amyl  alcohol  used  should  be  examined  by  evaporating  a 
quantity  as  large  as  that  used  in  the  analysis,  and  if  any  fixed 
residue  be  obtained,  or  if  a  solution  of  a  supposed  residue  in 
acidulated  water  give  reactions  with  general  reagents  for  alka- 
loids, then  the  portion  of  this  solvent  to  be  used  must  be  redis- 
tilled, after  adding  a  little  tartaric  acid.  To  decide  any  question 
as  to  results,  a  control  analysis  should  be  carried  in  a  parallel 
operation  upon  tissue  material  as  nearly  as  possible  the  same  as 
that  under  examination  for  poisons.  If  the  tissue  material  taken 
be  very  troublesome,  or  if  the  operator  prefer,  the  first  solution 
from  the  tissues  may  be  an  alcoholic  acidulous  solution,  and 
the  residue  from  the  evaporation  of  this  solution  may  be  taken 
up  by  water  (and  a  very  little  acid).  If  acetic  acid  be  used, 
care  must  be  taken  that  acid  reaction  with  litmus  be  main- 
tained. It  is  better  that  the  temperature  of  evaporations  be 
kept  below  80°  C.,  and  that  concentrations  be  hastened  by  a  re- 
duced air-pressure. 

The  recovery  of  morphine  from  the  body  in  cases  of  fatal 
poisoning  by  it  is  by  no  means  always  possible.  There  are 
numerous  recorded  cases  of  failure  of  competent  chemists  to 
find  this  alkaloid.  In  the  living  body  morphine  is  constantly 
undergoing  decomposition.  In  the  dead  body  it  may  suffer  de- 
composition at  a  very  slow  rate,  though  it  has  been  found  after 
standing  fourteen  months  in  putrefactive  liquids  (TAYLOR).  It 
is  highly  probable  that  morphine  undergoes  waste  by  decom- 
position during  a  prolonged  analytical  separation  from  tissues. 
On  the  other  hand,  when  an  analysis  is  commenced  immediately 
after  the  introduction  of  morphine  into  tissue  material,  ic  can  be 
recovered  with  less  waste  than  attends  some  much  more  'stable 
alkaloids,  probably  because  it  interposes  a  less  degree  of  adhesion 


372  OPIUM  ALKALOIDS. 

than  they.  In  experiments  instituted  by  the  author l  it  was 
found  that  the  loss  in  the  immediate  separation  of  morphine,  in 
its  smallest  recoverable  quantities,  from  an  avoirdupois  pound 
of  tissues,  was  not  over  one  hundred  times  the  quantity  needed 
for  recognition  by  the  test  of  Husemann. 

In  further  experiments  in  the  progress  of  the  same  investiga- 
tion,2 when  0.32  gram  of  morphine  was  administered  to  a  cat,  an 
analysis  commenced  40  minutes  afterward,  the  alkaloid  was  re- 
covered for  identification  from  the  stomach,  the  kidneys,  the 
urine,  and  from  the  blood,  but  not  from  the  liver.  In  four  ex- 
periments for  quantitative  recovery,  using  estimation  by  Mayer's 
solution,  results  were  obtained  as  follows :  In  each  instance  0.32 
gram  in  solution  was  introduced  directly  into  the  stomach  by  a 
stomach-tube ;  and  in  each  instance  the  stomach,  liver,  heart,  and 
kidneys  were  analyzed  together.  In  No.  4,  when  the  animal  was 
killed  30  minutes  after  the  administration,  and  the  analysis  be- 
gun at  once,  the  volumetric  result  indicated  the  recovery  of  0.25 
gram  of  alkaloid.  When  the  animal  was  killed  4  minutes  after 
the  introduction  into  an  empty  stomach,  symptoms  having  mean- 
time occurred,  and  the  body  then  left  for  two  days,  the  final  ti- 
tration  indicated  the  recovery  of  0.208  gram.  When  the  animal 
was  allowed  to  survive  the  administration  for  14  hours,  and  the 
analysis  then  at  once  commenced,  the  four  organs  gave  only  0.05 
gram  of  alkaloid.  On  the  repetition  of  the  last  experiment,  but 
with  a  delay  of  2  days  between  the  death  and  the  analysis,  0.0485 
gram  was  recovered. 

f. —  Quantitative. — Morphine  is  usually  dried  on  the  water- 
bath  for  weight  as  hydrate,  C17H19NO3 .  H2O  =  303,  5.94$  water. 

^'Control  Analyses  and  Limits  of  Recovery,"  1885:  Proc.  Am.  Asso. 
Adv.  Sci ,  34,  111 ;  Chem.  News,  53,  78,  et  seqJ  From  series,  each  of  four 
graded  trials,  by  the  method  of  separation  substantially  as  given  in  the  text, 
and  by  the  qualitative  test  with  sulphuric  and  nitric  acids,  the  following  limits 
of  recovery  were  fixed  for  a  good  color  test: 

From  64  grams  of  bread,   1  part  morphine  in  185185  parts. 
"      64        "        tissues,  1          "          "          142857     " 
"      64        "        liver,      1          "          "  142857     " 

These  "  tissues"  were  membranous,  as  the  coats  of  the  stomach,  and  con- 
taining much  less  fat  than  the  liver.  Trial  of  the  volumetric  estimation  of  the 
recovered  morphine,  when  larger  proportions  of  the  alkaloid  were  taken,  indi- 
cated a  much  greater  and  much  less  consistent  loss,  as  follows: 

From  128  grams  of  tissues,  1  part  morphine  in  19608  parts. 

"     128        'r        liver,     1          "         "  10870     " 

The  experiments  were  performed  by  Mr.  S.  G.  Steiner,  at  the  request  of  the 
author. 

2  Mr.  Steiner,  with  the  author,  in  1885,  unpublished. 


MORPHINE.  373 

(See  a.)  But  it  is  recommended  to  dry  at  a  temperature  not 
above  85°  C.  for  the  weight  of  the  hydrate,  or  at  near  120°  C. 
for  the  weight  of  the  anhydrous  alkaloid.  The  last-named  tem- 
perature is  sustained  by  the  anhydrous  alkaloid  without  loss  of 
weight. — The  washing  of  finely  crystallized  morphine  with  satu- 
rated morphine  solutions  has  been  resorted  to  by  Teschemacher 
and  others,  as  specified  further  on.  Still  well  (1886)  proposes  to 
estimate  the  meconate  of  lime  left  as  an  impurity  in  the  crys- 
tallized morphine  of  an  opium  assay  by  dissolving  and  washing 
with  hot  alcohol,  on  a  balanced  filter,  weighing  the  dried  resi- 
due, and  deducting  this  weight. 

Besides  this  gravimetric  determination  of  the  free  alkaloid 
there  is  no  well-established  method  of  estimating  morphine. 
The  method  next  to  be  named,  however,  is  the  volumetric  estima- 
tion with  Mayer's  solution  (see  Alkaloids,  Volumetric  Estima- 
tion of).  The  solution  is  adjusted,  if  necessary  by  a  preliminary 
assay,  to  be  of  the  strength  of  1  part  alkaloid  to  200  parts  of  the 
solution,  and  well  acidified  with  hydrochloric  or  sulphuric  acid 
(alcohol  and  acetic  acid  being  always  absent  in  this  estimation). 
Undoubtedly  the  composition  of  the  precipitate  is  varied  some- 
what by  conditions  of  concentration  and  preponderance  of  mass, 
as  occurs  with  other  alkaloids,  but  when  holding  the  concentra- 
tion uniform  by  a  preliminary  assay  (or  more  than  one)  the  main 
conditions  are  fixed.  Degrees  of  acidulation  have  little  effect 
(DRAGENDOKFF).  The  end-reaction  is  found  by  the  completion 
of  the  precipitate.  A  filtered  drop  is  tested  on  glass  slide  over 
black  paper,  with  a  drop  of  the  reagent ;  and  several  of  these 
test-portions  rinsed  from  time  to  time,  with  a  drop  or  two  of 
water,  into  the  solution  under  titration.  According  to  Mayer 
(1862),  and  Dragendorff  and  Kubly  (1874),  1  c.c.  of  Mayer's  so- 
lution indicates  0.020  gram  morphine  hydrate  or  0.019  gram 
anhydrous  morphine.  The  author  has  obtained  results  usually  a 
little  too  low  by  use  of  this  factor,  and  recommends  standardiz- 
ing the  Mayer's  solution  with  a  solution  of  pure  morphine  in 
acidulated  water,  in  conditions  of  concentration  and  temperature 
fixed  for  the  estimation.1  The  composition  of  the  precipitate  is 
given  under  d,  p.  369. 

An  estimation  of  morphine,  in  the  volumetric  and  coloro- 
metric  way,  by  iodic  acid,  was  given  by  STEIN  (1871),  by  MIL- 

1  DRAGENDORFF,  1874:  "  Werthbestimmung,"  p.  87.  A.  B.  PRESCOTT, 
1878:  Pro.  Am.  Pharm.,  26,  812;  Jour.  Ghem.  tioc.,  38,  192.  And  1880:  Am. 
Chem.  Jour.,  2,  301;  Jour.  Ghem.  Soc.,  42,  664.  The  aqueous  extract  of 
opium,  deprived  of  morphine,  yields  to  amyl  alcohol  bodies  giving  a  conside- 
rable precipitate  with  Mayer's  solution. 


374  OPIUM  ALKALOIDS. 

LEE  (1872),1  and  by  SCHNEIDER  (1881),  and  applied  to  the  assay 
of  opium.  Aqueous  iodic  acid  is  added  to  a  known  weight  of 
(opium)  solution,  and  after  the  lapse  of  a  few  minutes  the  libe- 
rated iodine  is  washed  out  by  shaking  with  carbon  disulphide. 
The  sample  color  thus  produced  is  then  compared  with  a  stan- 
dard color  obtained  in  the  same  manner  from  a  solution  of  mor- 
phine of  known  strength,  and  their  intensity  equalized  by  add- 
ing carbon  disulphide  to  the  deeper. — This  method  may  prove 
useful  in  certain  exigencies,  as  where  estimations  are  habitual 
and  there  is  nothing  present  besides  morphine  to  reduce  iodic 
acid.  The  details  of  the  method  as  improved  by  Schneider  are 
given  where  cited. 

KIEFFER'S  a  volumetric  estimation  of  morphine  consists  in  a 
measure  of  its  reduction  of  potassium  ferricyanide.  YENTURINI 
(1886  3)  finds  this  to  be  the  most  exact  of  the  volumetric  methods. 

Estimation  of  Morphine  in  Opium.  Processes  of  Morphio- 
metric  Assay.4 — The  following  is  the  process  of  the  U.  8.  Ph., 
adopted  in  the  Revision  qflS&Q: 

u  Opium,  in  any  condition  to  be  valued,  seven  grams  (7) ; 
lime,  freshly  slaked,  three  grams  (3) ;  chloride  of  ammonium, 
three  grams  (3);  alcohol,  [sp.  gr.  0.820J,  stronger  ether  [sp. 

1  Archiv  d.  Phar.  [2]  148,  150;  Phar.  Jour.  Trans.  [3]  2,  465;  Jour. 
Chem.  Soc.,  25,  180.  SCHNEIDER,  1881:  Archiv  d.  Phar.  [3]  19,  87;  Proc. 
Am.  Pharm.,  30,  232. 

2L.  KIEFFER,  1857:  Ann.  Chem.  Phar.,  103,  271. 

3  V.  VENTURTNI,  Q-azzetta  chim.  ital.,  16,  239;  Jour.  Chem.  Soc.,  50,  1086. 

4  In  the  text  following  are  given  the  processes  of  the  pharmacopoeias  of 
the  United  States,  England,  and  Germany,  with  commentary  upon  their  pro- 
visions, in  comparison  with  each  other.     Also,    the  detailed   process  of  Dr. 
Squibb,    the  directions  of   Prof.    Fliickiger  respecting  modifications  of  the 
method  of  the  Ph.  Germ.,  and  the  experimental  criticisms  of  Mr.  Conroy,  Mr. 
H.  Lloyd,  Mr.  Stillwell,  and  of  Messrs.  Wrampelmeier  and  Meinert,  with  cita- 
tions from  Portes  and  Langlois,  Prollius,  and  the  Soc.  de  Phar.  of  Paris. 

Of  further  literature  a  few  references  are  here  added:  PERGER,  1884:  Jour, 
prakt.  Chem.  [2]  29,  97;  Jour.  Chem.  Soc.,  46,  1217;  Pro.  Am.  Pharm.,  33, 
298.  PROCTER,  1871:  Am.  Jour.  Phar.,  43,  65.  ALESSANDRA,  1882:  Phar. 
Jour.  Irans.  [3]  n,  994;  Pro.  Am.  Pharm.,  30,  231.  A.  B.  PHESCOTT,  1878: 
with  STECHER,  Pro.  Am.  Pharm.,  26,  807;  Jour.  Vhem.  Soc.,  38,  191;  in  1880, 
"Report  on  Revision  U.  S.  Ph.,"  p.  102;  with  Moss,  1875:  Am.  Jour.  Phar., 
47,  460;  with  JOSEPH  F.  GEISLER,  1880:  "  Morphiometric  Methods,"  Ntw  Re- 
medies, 9,  356.  In  1883 :  '  •  On  the  Strength  of  Opium,"  etc.,  Pro.  Mich.  State 
Phar.  Assoc.,  i,  48  ;  The  Druggist,  6.  1.  Method  of  TESCHEMACHER,  1877: 
Chem.  News,  35,  47.  Report  of  T.  J.  WRAMPELMEIER  and  G.  MEINERT,  Mich. 
State  Phar.  Asso.,  Oct.  14,  1886;  Am.  Druggist,  New  York,  15,  203.  Report 
of  CHARLES  M.  STILLWELL,  1886:  Am.  Chem.  Jour.,  8,  295. 

A  "Bibliography  of  the  Opium  Assay"  is  in  preparation  by  Mr.  A.  Van 
Zwaluwenberg,  Ann  Arbor,  and  its  publication  is  promised  at  an  early  date. 


MORPHINE.  375 

gr.  0.725],  distilled  water,  each  a  sufficient  quantity.  Triturate 
together  the  opium,  lime,  and  20  c.c.  of  distilled  water,  in  a 
mortar,  until  a  uniform  mixture  results  ;  then  add  50  c.c.  of 
distilled  water,  and  stir  occasionally  during  half  an  hour.  Filter 
the  mixture  through  a  plaited  filter,  three  to  three  and  one-half 
inches  (75  to  90  millimeters)  in  diameter,  into  a 'wide-mouthed 
bottle  or  stoppered  flask  (having  the  capacity  of  about  120  c.c. 
and  marked  at  exactly  50  c.c.),  until  the  filtrate  reaches  this 
mark.  To  the  filtered  liquid  (representing  5  grams  of  opium) 
add  5  c.c.  of  alcohol  and  25  c.c.  of  stronger  ether,  and  shake 
the  mixture ;  then  add  the  chloride  of  ammonium,  shake  well 
and  frequently  during  half  an  hour,  and  set  it  aside  for  twelve 
hours.  Counterbalance  two  small  filters,  place  one  within  the 
other  in  a  small  funnel,  and  decant  the  ethereal  layer  as  com- 
pletely as  practicable  upon  the  filter.  Add  10  c.c.  of  stronger 
ether  to  the  contents  of  the  bottle  and  rotate  it ;  again  decant 
the  ethereal  layer  upon  the  filter,  and  afterward  wash  the  latter 
with  5  c.c.  of  stronger  ether,  added  slowly  and  in  portions. 
Now  let  the  filter  dry  in  the  air,  and  pour  upon  it  the  liquid 
in  the  bottle,  in  portions,  in  such  a  way  as  to  transfer  the  greater 
portion  of  the  crystals  to  the  filter. — Wash  the  bottle,  and  trans- 
fer the  remaining  crystals  to  the  filter,  with  several  small  por- 
tions of  distilled  water,  using  not  much  more  than  10  c.c.  in 
all,  and  distributing  the  portions  evenly  upon  the  filter.  Al- 
low the  filter  to  drain,  and  dry  it,  first  by  pressing  it  between 
sheets  of  bibulous  paper,  and  afterward  at  a  temperature  be- 
tween 55°  and  60°  C.  (131°  to  140°  F.)  Weigh  the  crystals  in 
the  inner  filter,  counterbalancing  by  the  outer  filter.  The  weight 
of  the  crystals  in  grams,  multiplied  by  twenty  (20),  equals 
the  percentage  of  morphine  in  the  opium  taken." 

The  Br.  Ph.,  in  the  Revision  of  1885,  adopted  the  following 
process  of  opium  assay:  "  Take  of  powdered  opium,  dried  at  100° 
O.,  140  grains  [9.072  grams];  lime,  freshly  slaked,  60  grains  [or 
3.9  grams]  ;  chloride  of  ammonium,  40  grains  [2.592  grams] ; 
rectified  spirit  (sp.  gr.  0.838),  ether  (sp.  gr.  0.735),  distilled 
water,  of  each  a  sufficiency. — Triturate  together  the  opium, 
lime,  and  400  grain-measures  [25.9  c.c.]  of  distilled  water  in  a 
mortar  until  a  uniform  mixture  results ;  then  add  1000  grain- 
measures  [64.8  c.c.]  of  distilled  water,  and  stir  occasionally  dur- 
ing half  an  hour.  Filter  the  mixture  through  a  plaited  filter, 
about  three  inches  in  diameter,  into  a  wide-mouthed  bottle  or 
stoppered  flask  ^having  the  capacity  of  about  six  fluid-ounces 
[Imp.  meas.,  or  170  c.c.]  and  marked  at  exactly  1040  grain- 
measures  [or  67.4  c.c.]),  until  the  filtrate  reaches  this  mark.  To 


3/6  OPIUM  ALKALOIDS. 

the  filtered  liquid  (representing  100  grains  [6.48  grams]  of 
opium)  add  110  grain-measures  [7.1  c.c.]  of  rectified  spirit  and 
500  grain-measures  [32.4  c.c.]  of  ether,  and  shake  the  mixture ; 
then  add  the  chloride  of  ammonium,  shake  well  and  frequently 
during  half  an  hour,  arid  set  it  aside  for  twelve  hours.  Counter- 
balance two  small  filters ;  place  one  within  the  other  in  a  small 
funnel,  and  decant  the  ethereal  layer  as  completely  as  practicable 
upon  the  inner  filter.  Add  200  grain-measures  [or  13  c.c.]  of 
ether  to  the  contents  of  the  bottle  and  rotate  it ;  again  decant 
the  ethereal  layer  upon  the  filter,  and  afterwards  wash  the  latter 
with  100  grain-measures  of  ether  added  slowly  and  in  portions. 
'Now  let  the  filter  dry  in  the  air,  and  pour  upon  it  the  liquid  in 
the  bottle  in  portions,  in  such  a  way  as  to  transfer  the  greater 
portion  of  the  crystals  to  the  filter.  When  the  fluid  has  passed 
through  the  filter,  wash  the  bottle  and  transfer  the  remaining 
crystals  to  the  filter,  with  several  small  portions  of  distilled 
water,  using  not  much  more  than  200  grain-measures  [or  13  c.c.} 
in  all,  and  distributing  the  portions  evenly  upon  the  filter.  Al- 
low the  filter  to  drain,  and  dry  it,  first  by  pressing  between  sheets 
of  bibulous  paper,  and  afterward  at  a  temperature  between  55a 
and  60°  C.  (131°-140°  F.),  and  finally  at  96°  to  100°  C.  (194°  to 
212°  F.)  Weigh  the  crystals  in  the  inner  filter,  counterbalanc- 
ing by  the  outer  filter."  The  weight  represents  the  quantity  of 
morphine  in  100  grains  [6.480  grams]  of  the  opium. 

The  process  of  the  PJi.  Germ.,  adopted  in  the  revision  of  1882, 
is  as  follows  :  Opium  is  to  be  dried  at  a  temperature  not  above 
60°  C.  Of  opium  powder  8  grams  are  to  be  agitated  with  80 

trams  of  water,  and  after  half  a  day  the  mixture  filtered.  Of  the 
Itrate  42.5  grams  are  treated  with  12  grams  of  alcohol  (sp.  gr. 
0.834-0.830),  10  grains  ether  (sp.  gr.  0.728-0.724),  and  1  gram 
of  ammonia  water  (sp.  gr.  0.960),  and  the  mixture  set  aside,  in  a 
stoppered  flask,  with  frequent  shaking,  for  24  hours,  at  a  tem- 
perature of  10°-15°  C.  The  contents  of  the  flask  are  then  brought 
upon  a  small  filter,  of  80  millimeters  (3-J-  inches),  previously 
dried  and  weighed.  The  crystals  recovered  from  the  filtered 
liquid  are  washed  on  the  filter  with  a  mixture  of  2  grams  diluted 
alcohol  (59.8$  to  61.5$  by  weight)  with  2  grains  of  water  and  2 
grams  of  ether,  applying  this  mixture  in  two  portions.  The 
filter  and  contents  are  dried  at  100°  C.  Deducting  the  weight 
of  the  filter,  the  weight  of  the  alkaloid  gives  the  quantity  of 
morphine  in  4  grams  of  opium. 

Tlie  three  pharmacopwial  processes  of  opium  assay  agree  in 
taking  a  stated  quantity  of  the  filtrate  to  represent  a  stated  frac- 
tion of  the  opium  taken,  thereby  avoiding  the  washing  of  the 


MORPHINE.  377 

undissolved  residue  of  opium,  and  without  concentration  obtain- 
ing a  solution  of  a  strength  desired  for  crystallization.  The 
quantity  of  filtrate  used,  in  proportion  to  the  total  quantity  of 
liquid  taken  with  dried  opium  for  the  mixture  filtered,  is  pro- 
vided in  each  of  these  respective  processes,  and  by  the  authors 
of  similar  processes,  as  follows  : 

U.  8.  Ph.  .  .  .  For  f  of  the  opium,  a  vol.  of  filtrate  =  f  £  vol.  of  liquids  taken. 
'Br.  Ph  .....  "  |  "  "  "  —  6  «»  «  « 

Soc.    Phar. 

Paris1....   "   fg  «•  "  "  =!§£      "  "  " 

FORTES  and 

LANGLOIS.2 
CONROY3..  . 

WRAMPEL- 

MEIER  and 

MEINERT, 

1886.4  ____  "    f  "  "  "  =  so 

Ph.  Germ...  "    £  "          weight       "  =  «i« 

PROLLIUS,    " 


18776...     „     4  „  <4  „  _48.5      <4  , 

PLUCKIGER,  f       »  "~  so^o 

1885  6...  j 

The  U.  S.  and  Br.  pharmacopoeias,  and,  earlier,  the  Pharma- 
ceutical Society  of  Paris,  take  out  of  the  filtrate  an  aliquot  por- 
tion of  the  total  volume  of  liquid  introduced  into  the  solution 
subjected  to  filtration,  making  no  allowance  for  the  volume  of 
solvents  being  increased  by  taking  solids  into  solution.  Still 
earlier  Portes  and  Langlois  seem  to  have  made  such  an  allow- 
ance by  the  increase  of  50  c.c.  to  53  c.c.  Mr.  Conroy  (1884) 
assumes  that  the  "  50  c.c.  contain  the  extractive  of  5  grams  of 
opium,  equal  to  about  3  grams  in-  the  moist  state  [italics  added] 
in  which  it  exists  in  opium.  This,  from  experiments  that  I 
have  tried,  increases  the  bulk  to  52  c.c." 

Recently  Messrs.  Wrampelmeier  and  Meinert  have  given 
(Loo.  cit.)  report  of  direct  experimentation  on  the  question 
"  whether  the  total  liquid  —  that  is,  the  70  c.c.  of  water  plus  the 

1  Societe  de  Pharmacie,  Paris  —  adoption  of  a  modification  of  the  process  of 
Portes  and  Langlois,  1882:  Phar.  Zeitung,  No.  6,  from  Jour,  de  Pharm.  d'  Al- 
sace-Lorraine ;  Am.  Jour.  Phar.,  54,  598. 

2  PORTES  and  LANGLOIS,  1881:  Jour,  de  Pharm.  et  de  Chim.,  1881,  399; 
New  Rem.,  n,  64;  Chem.  News,  45,  67. 

3  CONROY,  1884:  Phar.  Jour.  Trans.  [3]  15,  473. 

*  Proceedings  Mi  f-h.  State  Phar.  Asso.,  4,  127;  Am.  Druggist,  New  York, 
15,  203. 

6  PROLLIUS,  1877:  Schweiz.  Wochenschr.  f.  Phar.,  1877,  381;  Proc.  Am. 
Pharm.,  26,  276. 

•FLUCKIGER,  1885:  Archiv  der  Phar.  [3]  26  ;  Am.  Druggist,  14,  149. 
The  Ph.  Germ,  process  was  contributed  by  Pliickiger,  who  presents,  later, 
a  slight  modification,  noticed  in  the  text  further  on. 


378 


OPIUM  ALKALOIDS. 


extractive  matter  dissolved  thereby — is  really  more  in  volume 
than  70  c.c.  or  not."  These  experiments 1  obtained  an  average 
total  volume  of  liquid  of  but  TO.  29  c.c.,  and,  so  far  as  they  ex- 
tend, go  to  support  the  rate  adopted  by  the  U.  S.  Ph. — The 
method  of  the  Ph.  Germ,  and  of  Professor  Fliickiger,  in  which 
for  |-  of  the  opium  a  weight  of  filtrate  is  taken  equal  to  ||f  the 

'Following  is  the  original  report  of  the  experiments  of  Messrs.  Wrampel- 
meier  and  Meinert  (loc.  cit.) :  7  grams  of  powdered  opium  were  taken,  dried  at, 
100°  C.,  and  transferred  to  a  flask.  A  flask  was  used  instead  of  a  mortar,  in 
order  to  avoid  loss  by  evaporation.  Three  grams  of  freshly  slaked  lime  and  70  c.c. 
of  water  were  added,  the  whole  thoroughly  mixed  and  allowed  to  stand  for  half 
an  hour.  The  mixture  was  then  placed  upon  a  filter  and  (instead  of  50  c.c.) 
the  liquid  was  drained  off  as  much  as  possible  by  means  of  an  aspirator.  The 
filtrate  was  weighed,  and  its  specific  gravity  taken.  In  order  to  determine  how 
much  liquid  there  was  left  in  the  opium  on  the  filter,  the  filter  was  weighed 
with  the  funnel,  dried  at  100°  C  to  constant  weight,  and  again  weighed.  By 
multiplying  the  loss  in  weight  by  the  specific  gravity  of  the  filtrate,  the  weight 
of  the  liquid  left  in  the  opium  was  found.  In  the  same  manner  the  weight 
of  the  liquid  left  in  the  macerating  flask  which  could  not  be  brought  upon  the 
filter  was  determined.  The  weight  of  total  liquid  was  then  found  by  adding 
to  the  weight  of  the  filtrate  the  weight  of  liquid  left  in  the  opium  on  the  filter, 
and  that  of  the  liquid  left  in  the  flask,  and  from  this  the  total  volume — i.e., 
the  70  c.c.  plus  the  extractive  matter  dissolved  thereby — was  calculated  by  di- 
viding by  the  specific  gravity. 

On  working  two  samples  of  powdered  opium  in  this  way,  the  volume  was 
found  to  be  in  the  one  case  70.83  c.c.,  and  in  the  other  it  was  70.85  c.c. ;  where- 
as, according  to  Conroy,  the  volume  should  be  72.8  c.c.  Since  the  U.  S.  Ph. 
directs  to  take  opium  in  any  form,  it  seemed  possible  that,  if  lump  opium 
which  contains  some  moisture  be  used,  the  volume  of  liquid  might  be  increased. 
A  sample  of  lump  opium  was  taken  which  contained  11  per  cent,  of  moisture. 
Seven  grams  were  weighed  off,  cut  into  small  pieces,  and  transferred  to  a  flask. 
Then  the  lime  and  70  c.c.  of  water  were  added,  the  whole  thoroughly  mixed 
by  means  of  a  stirring  rod  until  a  uniform  mixture  was  obtained.  The 
mixture  was  then  allowed  to  stand  for  half  an  hour  and  finally  placed  upon  a 
filter.  The  filtrate  was  weighed  and  its  specific  gravity  taken,  and  the  weight 
of  the  liquids  left  in  the  opium  on  the  filter,  and  that  of  the  liquid  left  in  the 
flask,  were  calculated  in  the  above-described  manner.  Experiments  made  with 
two  samples  gave  the  following  results: 


/Specific  gravity  of 
filtrate, 

Per  cent, 
of  morphine- 

Total  liquid. 

Experiment  I  

1.01270 
1.01265 

1  O"P 

8.3    per  cent. 
9.04 

70.39  c.c. 
70.  19  c.c. 

Experiment  II 

Aver 

70.29  c.c. 

This  gave  an  average  increase  of  0.29  c.c.  Then  a  very  moist  lump  opium 
containing  20.7  per  cent,  moisture  was  used,  and  the  volume  of  liquid  was  found 
to  be,  in  this  case,  70.61  c.c.  These  experiments,  therefore,  would  seem  to 
prove  that  the  volume  of  filtrate  directed  to  be  taken  by  the  Pharmacopoeia 
(50  c.c.)  is  nearly  correct. 


MORPHINE.  379 

weight  of  the  liquids  used  with  the  dry  opium,  depends  upon 
dry  opium  containing  |  of  its  weight  (62. 5$)  of  soluble  mat- 
ter. The  proportion  of  soluble  matter  in  opium  is,  at  all  events, 
quite  variable*. 

HERBERT  LLOYD'  found  that  when  morphine  itself  is  sub- 
jected to  the  U.  S.  Ph.  process  of  assay,  it  suffers  a  loss  equal 
to  from  0.060  to  0.089  gram  on  the  yield  of  the  50  c.c.,  greater 
or  less  according  to  the  taking  of  greater  or  smaller  quantities 
of  morphine.  Of  course  it  should  be  understood  that  an  alka- 
loid cannot  be  obtained  by  a  single  crystallization,  as  in  all 
established  methods  of  the  morphiometric  assay  of  opium,  with- 
out some  loss ;  nevertheless  the  result  becomes  practically  a  true 
one  when  the  quantity  of  the  loss  is  made  to  equal  an  average 
balance  of  the  quantity  of  impurity  remaining  in  the  crystals 
weighed.  It  appears  from  all  evidences  to  be  not  improbable 
that,  by  the  U.  S.  Ph  or  Br.  Ph.  process,  the  loss  of  weight 
of  real  morphine,  whatever  its  sources,  exceeds  the  weight  of 
impurity  with  the  morphine. 

The  quantity  of  ammonium  chloride  introduced  into  the 
filtrate  is  to  the  quantity  of  dried  opium  represented  in  the 
filtrate,  by  the  directions  of  the  U.  S.  Ph.  as  well  as  by  the 
process  of  Portes  and  Langlois,  in  the  proportion  of  3  :  5 ;  by 
the  Br.  Ph.  it  is  2  :  5.  Mr.  Conroy  (where  cited)  reports  ex- 
periments showing  that  excess  of  ammonium  chloride  causes 
proportional  diminution  of  yield.  The  truth  of  this  conclusion 
has  been  confirmed  by  Messrs.  Wrarnpelrneier  and  Meinert 
(1886,  loo.  tit.)  From  these  observations  and  those  of  Lloyd 
(loc.  cit.)  it  appears  that  morphine  and  lime  exert  a  mutual  sol- 
vent action  on  each  other,  and  that  other  constituents  of  opium 
help  to  dissolve  lime.  The  more  lime  the  more  free  ammonia. 
And  both  free  ammonia  and  remaining  ammonium  chloride  help 
to  dissolve  the  morphine.2  It  appears,  therefore,  that  the  pro- 

1ISS5:  Am.  Druggist,  New  York,  14,  221. 

5  "  In  order  to  find  out  whether  the  morphine  is  held  in  solution  by  the 
excess  of  ammonia  liberated  or  by  the  excess  of  ammonium  chloride,  the  fol- 
lowing experiments  were  made.  By  calculation  it  was  found  that,  when  0.202 
gram  of  calcium  oxide  is  in  solution,  0.399  gram  of  ammonium  chloride 
is  decomposed.  Subtracting  this  from  3  grams,  we  find  that  in  this  case 
there  is  an  excess  of  2.61  grams  of  ammonium  chloride  present  in  the  assay 
liquor.  This  amount  of  ammonium  chloride  was  then  dissolved  in  50  c.c.  of 
pure  water  and  0.500  gram  of  morphine  added,  and  the  solution  allowed  to 
stand  for  12  hours,  after  which  time  0.500  gram  of  morphine  had  lost  0.135 
gram.  The  amount  of  ammonia  which  would  be  set  free  in  such  assay  was 
also  calculated,  and  a  solution  of  50  c.c.  of  pure  water  containing  lhat  amount 
of  ammonia  was  found  to  dissolve,  after  12  hours'  standing,  0  110  gram  of  mor- 
phine. Thus  it  was  shown  that  both  ammonium  chloride  and  free  ammonia  in 


380  OPIUM  ALKALOIDS. 

portion  of  ammonium  chloride  directed  by  the  Br.  Ph.  is  advis- 
able. 

The  quantity  of  free  ammonia  liberated  from  the  ammo- 
nium chloride  in  the  filtrate  is  limited  by  the  slight  but  vary- 
ing solubility  of  the  lime.  The  excess  of  lime  in  the  primary 
maceration  serves  to  improve  the  consistence  of  the  mucila- 
ginous matters  of  the  opium,  favoring  solution  and  filtration. 
This  use  of  lime  in  excess,  which  first  holds  the  alkaloid  mor- 
phine in  an  alkaline  solution,  and  afterward,  in  the  filtrate,  be- 
comes exchanged  for  free  ammonia,  (2NH4C1  -)-  Ca(OH)2  = 
2NH3  +  CaClg  +  2II2O),  is  credited  to  the  plan  of  MOHE. 
Whether  liberated  by  lime  from  ammonium  chloride,  or  added 
in  water  of  ammonia  (as  by  the  Ph.  Germ.),  at  all  events  free 
ammonia  is  employed  in  separating  morphine  from  its  com- 
pounds, to  crystallize  on  standing,  in  all  methods  of  morphio- 
metric  assay  so  far  well  established  in  use. — The  crystallization 
of  the  alkaloid  requires  time.  In  the  Hager-Jacobsen  processes 
crystallization  was  promoted,  and  the  crystals  purified,  by  the 
addition  of  email  quantities  of  ether  and  benzene,  not  too  much 
to  be  taken  into  solution  in  the  crystallizing  liquid.  The  use  of 
an  excess  of  ether,  much  beyond  ether-saturation,  so  as  to  cause 
an  ether  layer  to  rise  above  the  crystallizing  liquid,  along  with 
the  frequent  shaking  up  of  the  ether  with  the  aqueous  liquid  in 
the  closed  fiask  during  crystallization,  marks  an  important  prac- 
tical advance  in  opium  assay.  This  use  of  ether,  introduced 
about  1881,  has  been  adopted  in  each  of  the  three  pharmaco- 
poeial  processes  above  given,  also  in  the  processes  on  individual 
authority,  as  hereafter  presented.  By  this  use  of  immiscible 
ether  in  forcible  contact  by  agitation  with  the  aqueous  solution, 
crystallization  is  greatly  quickened,  and  purer  crystals  are  ob- 
tained. The  effect  of  stirring  was  emphasized  in  1877  by  Tesche- 
macher,  who  says :  "  The  rapid  and  continuous  stirring  is  most 
important,  as  the  precipitation  of  the  whole  morphine  in  fine 
powder  is  thereby  effected,  instead  of  the  granular  or  mamrnil- 
lated  condition  so  frequently  met  with."  This  effect  on  crystal- 
line precipitates,  in  numerous  analytical  operations,  is  well  under- 
stood at  present.  The  addition  of  alcohol,  in  the  crystallizing 
liquid,  is  well  understood  to  cause  whiter  and  finer  crystals  to 
be  obtained,  but,  unless  counteracted  with  ether  or  by  greater 

solution  exert  a  distinct  solvent  action  upon  the  alkaloid.  It  is  therefore 
probable  that  by  using  about  1.000  gram  of  ammonium  chloride  instead  of 
3.000  grams,  the  amount  of  morphine  held  in  solution  will  be  greatly  re- 
duced."— WRAMPELMEIER  and  MEINEBT,  1886:  Am.  Druggist,  New  York,  15, 


MORPHINE.  381 

•concentration,  alcohol  in  proportion  to  its  quantity  tends  to  di- 
minish the  yield  of  crystals.  By  the  processes  of  the  Ph.  Germ, 
and  Professor  Fliickiger,  alcohol,  ether,  and  aqueous  liquid  hold 
the  proportions  by  weight  12  :  10  :  43.5  in  the  crystallizing 
liquid.  By  the  Br.  Ph.  process  these  proportions  are  by  volume 
nearly  as  4  :  2  J  :  41  ;  and  by  the  U.  S.  Ph.  process,  as  5  :  25  :  50. 
That' is,  for  100 parts  ~by  weight  of  aqueous  solution,  the  crys- 
tallizing liquid  contains,  in  parts  by  weight,  nearly  as  follows  : 


U.  S.  Ph. 

Br.  Ph. 

Ph.  Germ. 

Of  Alcohol     .  . 

8  (sp  ffr   0  820) 

9  (sp.  gr.  0.838) 

28  (sp.  gr.  0.832) 

-Of  Ether  ...     . 

35  (sp.  gr.  0  725) 

35  (sp.  gr.  0.735) 

23  (sp.  gr.  0.726) 

The  directions  given  by  Prof.  Fluckiger.  in  1885,1  slightly 
modified  from  those  of  the  Ph.  Germ.,  are  as  follows  :  u  Place  8 
grams  of  powdered  opium  upon  a  filter  of  80  millimeters 
{3-J-  inches)  diameter,  and  wash  it  gradually  with  18  grams 
(or  25  c.c.)  of  ether,  the  funnel  being  kept  well  covered ;  force 
out  the  last  drops  of  filtrate  by  tapping  the  funnel,  dry  the 
opium  on  a  water-bath,  transfer  it  to  a  small  flask  containing  80 

frams  of  water  at  25°  C.,  and  shake  well  repeatedly.  After  12 
ours  pour  the  mixture  on  the  previously  used  filter,  and  collect 
42.5  grams  of  the  filtrate  in  a  small  flask,  to  which  add  12  grams 
of  alcohol  [sp.  gr.  0.832],  10  grams  of  ether  [sp.  gr.  0.726],  and 
1  gram  of  ammonia-water  [sp.  gr.  0.960],  stopper  well,  set  aside 
.at  a  temperature  of  12°tol5°C.,  and  shake  repeatedly.  After 
24  hours  moisten  a  new  tared  filter  of  80  millimeters  [34  inches] 
diameter  with  ether,  pour  upon  it  the  ethereal  layer  in  the  flask, 
add  10  more  grams  [14  c.c.]  of  ether  to  the  latter,  and  shake  well. 
Again  pour  the  ethereal  layer  upon  the  filter.  When  this  has 
passed,  pour  the  whole  contents  of  the  flask  upon  the  filter,  and 
wash  the  crystals  of  morphine  twice  with  a  mixture  of  2  grams 
of  diluted  alcohol  (sp.  gr.  0.892),  2  grams  of  water,  and  2  grams 
of  ether.  Dry  at  a  gentle  heat,  finally  at  100°C.,  and  weigh, 
adding  the  morphine  which  may  still  adhere  to  the  inside  of  the 
flask."  Prof.  Fliickiger  prefers  to  weigh  the  morphine  in  the  flask 
instead  of  on  the  filter. 

The  concentration  of  the  (aqueous)  solution  set  for  the  crys- 
tallization of  the  morphine  in  an  opium  assay  is  very  nearly  1  to 
10,  the  same  in  each  of  the  four  processes  which  have  been  given 
-those  of  the  Ph.   Germ.,    Br.   Ph.,  U.   S.  Ph ,  and  Professor 

1  See  foot-note  on  p.  377. 


382          p  OPIUM  ALKALOIDS. 

Flnckiger.  In  these  processes  10  c.  c.  of  water  are  taken  for  each 
1  gram  of  opium,  with  little  addition  to  alter  this  proportion, 
which  is  nearly  retained  in  the  crystallizing  liquid.1  In  the  pro- 
cess next  to  be  given,  that  of  Dr.  Squibb,  the  plan  of  using  an 
aliquot  part  of  the  digestive  solution  is  rejected.  The  undis- 
solved  residue  of  opium  is  to  be  exhausted  and  washed  clean,  the 
total  filtrates  reaching  near  20  c.c.  for  each  1  gram  of  opium. 
The  entire  solution  is  to  be  reduced  in  volume  by  evaporation, 
the  washings  separately,  until  brought  to  about  2  c.c.,  increased, 
by  transfer  rinsing  and  by  ammonia-water,  to  about  3  c.c.  of 
crystallizing  liquid  for  1  gram  of  the  opium  taken.  The  ether, 
of  course,  is  not  to  be  counted  as  solvent,  since  it  serves  as  an 
anti-solvent  in  all  the  processes.  This  greater  concentration  of 
volume  undoubtedly  diminishes  the  loss 3  due  to  morphine  left  in 
the  mother-solution,  and  increases  the  gain  due  to  impurities  held 
in  the  morphine  crystals.3  The  relation  between  this  loss  and 
this  gain,  in  opium  assay,  was  mentioned  on  p.  379. 

The  process  of  Dr.  E.  R.  tiquibb*  published  in  1882,  is  as 
follows:  "  Take  of  opium  in  its  commercial  condition5  10  grams 

1  Wrampelmeier  and  Meinert  (loc.  cit.)  object  to  the  U.  S.  Ph.  direction  to 
triturate  and  digest  in  an  open  mortar,  and  to  measure  in  a  wide-mouthed  bot- 
tle or  flask,  as  liable  to  cause  some  concentration  by  evaporating.     Such  con- 
centration of  volume  interferes  with  the  principle  of  taking  an  aliquot  part, 
and  tends  toward  too  high  results. 

2  "  About  10  per  cent,  of  the  morphine  in  the  opium  is  retained  in  the 
mother-liquor  after  crystallizing  the  morphine  according  to  the  U.  S  Ph."- 
"In  order  to  determine  how  much  of  the  alkaloid  is  dissolved  in   the  mother- 
liquor  after  crystallizing  the  morphine,  a  solution  was  made  to  correspond  as 
nearly  as  possible  to  the  assay  liquor,  and  then  a  certain  amount  of  morphine 
was  used.     The  amount  of  lime  (CaO)  found  to  be  present  in  the  mother-liquor 
of  the  lump  opium  was  0.202  gram.    This  amount  of  lime  was  taken,  slaked  with 
a  little  water,  transferred  to  the  flask,  and  50  c.c.  of  distilled  water  were  added. 
On  adding  then  0.500  gram  of  pure  morphine  it  was  found  that  some  of  the 
lime  was  left  undissolved.     Therefore,  in  another  trial,  a  little  less  calcium  ox- 
ide was  used,  the  50  c.c.  of  water  and  0.500  gram  of  morphine  added.     Then, 
as  in  the  U.  S.  Ph.  process,  5  c.c.  of  alcohol,  and  25  c.c.  of  ether,  and  3  grams 
of  ammonium  chloride  were  added,  and  the  mixture  allowed  to  stand  for  12 
hours.     The  amount  of  morphine  obtained  was  0.442  gram,  showing  that  of  the 
0.500  gram  taken  0.058  gram  was  retained  in  solution  in  the  mother-liquor." — 
WRAMPELMEIER  and  MEINERT,  Am.  Druggist,  New  York,  15,  203. 

3  "The  precipitate  of  morphine  obtained  by  Dr.  Squibb's  process  contains 
insoluble  matter,  resinous  and  other  organic  matters  soluble  in  alcohol,  and 
meconate  of  lime,  the  latter  constituting  about  25  per  cent,  of  the  impurities 
present.     The  average  amount  of  the  impurities  present  in  the  crystals  obtained 
by  his  process  is  8  percent,  of  the  weight  of  the  crystals." — CHARLES  M.  STILL- 
WELL,  Am.  Chem.  Jour.,  8,  306. 

4 1882:  Ephemeris,  I,  14;  Jour.  Chem.  Soc.,  42,  666.  Further,  see  WAIN- 
WRIGHT,  1885:  Jour.  Am.  Chem.  Soc.,  7,  45. 

6  "  If  of  lump  opium,  every  tenth  lump  of  a  case  should  be  sampled  by  cut- 
ting out  a  cone-shaped  piece  from  the  middle  of  the  lump.  Then  from  the  side 


MORPHINE.  383 

(154.32  grains).  Put  the  weighed  portion  in  a  flask,  or  common 
wide-mouthed  vial  of  120  c.c.  (4  f.  oz.)  capacity,  tared  and  fitted 
with  a  good  cork.  Add  100  c.c.  (3.3  f.  oz.)  of  water,  and  shake 
well.  Allow  it  to  macerate  over-night,  or  for  about  12  hours, 
with  occasional  shaking,  and  then  shake  well  and  transfer  the 
magma  to  a  filter,  of  about  10  centimeters  (4  inches)  diameter, 
which  has  been  placed  in  a  funnel  and  well  wetted.1  Filter  off 
the  solution  into  a  tared  or  marked  vessel,  then  percolate  the 
residue  on  the  filter  with  water  dropped  on  the  edges  of  the  fil- 
ter and  on  the  residue,  until  the  filtrate  measures  about  120  c.c. 
(4  f.  oz.),  and  set  this  strong  solution  aside.  Then  return  the 
residue  to  the  bottle  by  means  of  a  very  small  spatula,  without 
breaking  or  disturbing  the  filter  in  the  funnel,  add  30  c.c. 
(1  f.  oz.)  water  and  shake  well,  and  return  the  magma  to  the 
filter.  When  drained  rinse  the  bottle  twice,  each  time  with 
10  c.c.  (\  f.  oz.)  water,  and  pour  the  rinsings  upon  the  residue. 
When  this  has  passed  through,  wash  the  filter  and  residue  with 
20  c.c.  (f  f.  oz.)  of  water,  applied  drop  by  drop  around  the  edges 
of  the  filter  and  upon  the  contents.  When  the  filter  has  drained 
there  should  be  about  70  c.c  (2f  f.  oz.)  of  the  weaker  solution.2 
The  filter  and  residue  are  now  to  be  dried  until  they  cease  to  lose 
weight  at  100°  C.  If  any  residue  remains  in  the  bottle,  the  bot- 
tle is  also  to  be  dried  in  an  inverted  position  and  weighed.  [The 
weights  show  the  quantity  of  insoluble  matter  in  the  opium.] 
Evaporate  the  weaker  solution  in  a  tared  capsule  of  about  200 
c.c.  (6f  f.  oz.)  capacity,  without  a  stirrer,  on  a  water-bath  until 

of  the  cone  a  small  strip  is  taken  from  point  to  base,  not  exceeding  say  half  a 
gram  from  cones  which  would  average  10  to  15  grams.  The  little  strips  are 
then  worked  into  a  homogeneous  mass  by  the  fingers,  and  the  mass  is  then 
wrapped  in  tin-foil  to  prevent  drying,  until  it  can  be  weighed  off  for  assay. 
When  opened  to  be  weighed  off  it  is  best  to  weigh  off  at  once  three  portions  of 
10  grams  each.  In  one  portion  the  moisture  is  determined  by  drying  it  on  a 
tared  capsule  until  it  ceases  to  lose  weight  at  100°  C.  Another  portion  is  used 
for  the  immediate  assay,  and  the  third  is  reserved  for  a  check  assay  if  desira- 
ble." .  .  .  Opium  "should  not  be  dried,  but  should  be  weighed  for  the  assay  in 
the  condition  in  which  it  is  found  in  the  market,  and  in  which  it  is  to  be  dis- 
pensed." 

1  "If  the  shaking  be  frequent  and  active,"  "the  time  of  maceration  can 
easily  be  shortened  even  to  three  hours."    The  author  of  the  process  states  that 
exceptional  opiums  give  a  magma  which  will  not  filter,  and  advises  to  treat 
such  with  ether  before  the  assay,  washing  in  a  bottle  with  30  c.c.  ether,  shak- 
ing well,  and  washing  further  with  10  c.c.  ether  and  drying  on  a  filter. 

2  "  This  (120  +  70  =  )  190  c.c.  (6£  f.  oz.)  of  total  solution  will  practically  ex- 
haust almost  any  sample  of  opium.    But  occasionally  a  particularly  rich  opium, 
or  one  in  coarse  powder,  or  an  originally  moist  opium  which  has  by  slow  drying 
become  hard  and  flinty,  will  require  further  exhaustion.     In  all  such  cases,  or 
cases  of  doubt,  the  residue  should  be  again  removed  from  the  filter  and  shaken 
with  oO  c.c.  (1  f.  oz.)  of  water,  and  returned,  and  be  again  washed  as  before." 


384  OPIUM  ALKALOIDS. 

reduced  to  about  20  grams  (309  grains).  Now  add  the  120  c.c. 
of  stronger  solution,  and  evaporate  the  whole  again  to  about  20 
grams  (309  grains). 

"When  cool  add  5  c.c.  (0.17  f.  oz.)of  alcohol  (sp.  gr.  0.820), 
and  stir  until  a  uniform  solution  is  obtained  and  there  is  no  ex- 
tract adhering  undissolved  on  the  capsule.1  Pour  the  concen- 
trated solution  from  the  capsule  into  a  tared  flask  of  about  100  c.c. 
(3J  f .  oz.)  capacity,  and  rinse  the  capsule  into  the  flask  with  about 
5  c.c.  of  water  used  in  successive  portions. — Then2  add  30  c.c. 
(1  f.  oz.)  of  ether,  and  shake  well.  Add  now  4  c.c.  (0.133  f .  oz.) 
of  water  of  ammonia  of  ten  per  cent.  (sp.  gr.  0.960),  and  shake 
the  flask  vigorously  until  the  crystals  begin  to  separate.  Then 
set  the  flask  aside  in  a  cool  place  for  12  hours,  that  the  crystalli- 
zation may  be  completed.3 — Pour  off  the  ethereal  stratum  from 
the  flask,  as  nearly  as  possible,  on  to  a  tared  filter  of  about  10 
centimeters  (4  inches)  diameter,  well  wetted  with  ether.  Add 
20  c.c.  (f  f.  oz.)  of  ether  to  the  contents  of  the  flask,  rinse  round 
without  shaking,  and  again  pour  off  the  ethereal  stratum  as  closely 
as  possible  on  to  the  filter,  keeping  the  funnel  covered.  When 
the  ethereal  solution  is  nearly  all  through,  wash  down  the  edges 
and  sides  of  the  filter  with  5  c.c.  (0.  17  f .  oz.)  of  ether,  and  allow 
the  filter  to  drain  with  the  cover  off.  Then  pour  on  the  remain- 
ing contents  of  the  flask  and  cover  the  funnel.  When  the 
liquid  has  nearly  all  passed  through,  rinse  the  flask  twice  with 
5  c.c.  (0.17  f.  oz.)  of  water  each  time,  pouring  the  rinsings  with 
all  the  crystals  that  can  be  loosened  on  to  the  filter,  and  dry  the 
flask  in  an  inverted  or  horizontal  position,  and,  when  thoroughly 
dry,  weigh  it.  Wash  the  crystals  with  10  c.c.  (J  f.  oz.)  of  water 
applied  drop  by  drop  to  the  edges  of  the  filter.  When  drained, 
remove  the  filter  and  contents  from  the  funnel,  close  the  edges  of 
the  filter  together,  and  compress  it  gently  between  many  folds  of 
bibulous  paper.  Then  dry  it  at  100°  C.  and  weigh  it.  Remove 
the  crystals  of  morphine  from  the  filter,  brush  it  off,  and  re- 
weigh  it  to  get  the  tare  to  be  subtracted.  The  remainder, 
added  to  the  weight  of  the  crystals  in  the  flask,  will  give  the 
total  yield  of  morphine  in  clean,  distinct,  small  light-brown 
crystals." 

1  "  If  this  solution  should  contain  an  appreciable  precipitate,  as  from  rare 
specimens  of  opium  it  will,  it  must  be  filtered,  and  the  filter  be  carefully  wash- 
ed through.     Then  the  filtrate  must  be  evaporated  to  25  or  30  grams." 

2  "If  it  has  been  filtered  and  evaporated,  add  10  c.c.  (\  f.  oz.)  of  alcohol 
and  shake  well." 

3  "  If  the  shaking  be  frequent  and  vigorous,  2  or  3  hours'  time  will  be  suf- 
ficient to  complete  the  crystallization;  or  if  it  be  continuous,  half  an  hour  will 
be  sufficient,  but  as  a  rule  it  is  better  to  allow  the  flask  to  stand  over-night." 


MORPHINE.  335 

As  to  the  tests  for  purity  of  the  recovered  morphine,  see  g, 
p.  386. 

To  effect  a  complete  washing  of  the  crystallized  morphine 
without  loss,  TESCHEMACHEK,  in  1877, '  resorted  to  the  use  of  a 
saturated  aqueous  solution  of  morphine  and  a  saturated  alcoholic 
solution  of  morphine  as  washing  liquids.  The  "  rnorphiated 
water"  was  simply  a  saturated  solution,  and  contained  0.04  per 
cent,  of  the  alkaloid.  The  "  morphiated  spirit  "  was  prepared 
by  mixing  1  part  of  ammonia-water,  sp.  gr.  0.880,  with  20  parts 
of  (methylated)  alcohol,  and  digesting  a  large  excess  of  morphine 
in  this  mixture  for  several  days.  It  contained  0.33  per  cent,  of 
morphine.  STILLWELL,  1886,a  adopts  this  way  of  washing  the 
crystallized  morphine  obtained  by  Squibb's  process.  He  col- 
lects the  crystals  on  balanced  filter-papers  of  4£  inches  diameter. 
The  ethereal  stratum  of  the  crystallizing  liquid  is  poured  through 
the  filter,  washing  out  several  times  with  10  c.c.  of  ether,  rinsing 
the  flask  around  without  shaking  it,  letting  settle  for  a  few  minutes, 
and  decanting  upon  the  filter.  If  the  aqueous  solution  pass 
on  to  the  filter  it  is  of  no  importance.  The  washing  with  ether 
is  followed,  first,  by  a  thorough  washing  with  the  "  morphiated 
spirit,"  then  by  a  thorough  washing  with  the  "  morphiated 
water,"  and,  after  draining,  by  two  more  washings  of  10  c.c. 
each  of  "  morphiated  spirit."  After  draining  a  few  minutes, 
while  the  funnel  is  covered  with  a  watch-glass,  two  additional 
washings,  each  with  10  c.c.  of  ether,  are  made.  "  This  will  re- 
move any  narcotine  which  may  have  been  left  from  the  evapora- 
tion of  the  ethereal  solution  at  the  beginning  of  the  operation. 
The  paper  and  contents  are  thus  left  in  a  condition  to  be  rapidly 
dried.  Let  the  filter  and  its  contents  stand  exposed  for  a  few 
minutes,  and  then  dry  at  100°  C.  and  weigh.  Twenty  minutes' 
or  half  an  hour's  drying  is  usually  sufficient." 

The  purification  of  the  crystals  from  meconate  of  lime  and 
any  other  matters  insoluble  in  hot  alcohol,  as  used  by  Stillwell, 
was  stated  on  page  373. 

The  Estimation  of  Morphine  in  Tincture  of  Opium. — The 
following  are  the  directions  of  Mr.  H.  B.  PARSONS  in  application 
of  the  U.  S.  Ph.  process  of  morphine  estimation  to  laudanum.8 
Of  the  laudanum  75  c.c.  are  evaporated  to  dryness  on  the  water- 

1  E.  F.  TESCHEMACHER,  Chem.  News,  35,  47;  Jour.  Chem.  Soc.,  32,  231- 
232. 

2  CHARLES  M.  STILLWELL,  Am.  Chem.  Jour.,  8,  295. 

3  "  The  Composition  of  the  Laudanum  generally  dispensed  in  the  State  of 
New  York,"  with  report  of  forty-eight  samples,  1883:  New  York  State  Phar. 
Asso.,  New  Rem.,  12,  194. 


386  OPIUM  ALKALOIDS. 

bath.  When  cool,  75  c.c.  of  water  are  added,  together  with  3 
grams  of  water-slaked  lime.  Thorough  admixture  is  attained  by 
trituration  at  intervals  during  half  an  hour.  The  liquid  is  fil- 
tered (from  calcium  meconate  and  other  insoluble  matters),  and 
50  c.c.  of  the  filtrate  (representing  50 c.c.  of  laudanum)  is  placed 
in  an  assay-flask  for  treatment.  Now  add  alcohol  (sp.  gr.  0.820), 
5  c.c.  ;  ether  (sp.  gr.  0.725  or  lower),  25  c.c.  ;  ammonium  chlo- 
ride, 3  grams.  Shake  the  mixture  in  the  corked  flask  several  times 
during  the  first  half-hour,  and  occasionally  afterward.  After  12  or 
more  hours'  standing  the  crystals  are  gathered  on  a  small  balanced 
filter,  slightly  washed  with  cold  water,  dried  at  ^60°  C.  (140°  F.), 
and  weighed.  The  grams  of  this  weight,  multiplied  by  2  (for 
100  c.c.  of  the  laudanum)  and  by  the  specific  gravity  of  the 
laudanum,  equal  the  per  cent,  of  morphine  in  the  sample  assayed. 
Tincture  of  opium  of  the  U.  S.  Ph.,  1880,  is  required  to  be 
made  from  one-tenth  its  weight  of  dry  opium  (powdered  opium, 

g. — Impurities. — "On  adding  20  parts  of  colorless  solution 
of  soda  or  potassa  to  1  part  of  morphine,  a  clear,  colorless  solu- 
tion should  result,  without  residue  (absence  of  other  alkaloids)" 
(U.  S.  Ph.)  "The  watery  solution  of  morphine  salt  is  readily 
made  turbid  by  addition  of  potassium  carbonate.  Ammonia 
gives  a  precipitate  not  sensibly  soluble  in  excess  of  ammonia  or 
in  ether,  but  soluble  both  in  lime  solution  and  in  soda  solution  " 
(Ph.  Germ.) 

u  Take  a  small  portion  of  the  crystals  [free  morphine  from 
the  opium  assay],  rub  them  into  very  fine  powder,  and  weigh  off 
0.1  gram.  Put  this  in  a  large  test-tube  fitted  with  a  good  cork, 
and  add  10  c.c.  of  officinal  lime-water.  Shake  occasionally, 
when  the  whole  of  the  powder  should  dissolve  (absence  of  nar 
cotine) "  (FLUCKIGEK,  SQUIBB).  "  The  lime-water  test  for  the 
narcotine  in  the  results  of  the  assay  is  quite  sufficient,  since  no- 
thing, except  coloring  matter,  is  so  likely  or  so  liable  to  be  present 
as  narcotine.  The  only  difficulty  is  to  know  when  the  lime 
water  has  surely  dissolved  all  it  will  dissolve.  This  is  facilitated 
by  having  a  very  fine  powder,  and  then  good  judgment  is  re- 
quired to  know  the  value  or  significance  of  undissolved  residues 
when  they  are  small"  (E  E.  SQUIBB,  1882). 

"  Morphine  yields  a  colorless  solution  with  cold  concentrated 
sulphuric  acid,  which  should  not  acquire  more  than  a  reddish 
tint  by  standing  some  time"  (U.  S.  Ph.)  This  test,  applied 
with  care,  gives  good  comparative  indications  of  the  proportions 
of  narcotine. 


NARCOTINE.  387 

If  0.5  gram  of  morphine  sulphate  be  dissolved  in  15  c.c.  of 
water,  with  the  addition  of  5  drops  of  sulphuric  acid,  and  the 
solution  washed  with  four  or  five  portions  each  of  25  c.c.  of 
stronger  ether,  and  the  united  ethereal  solutions  be  evaporated, 
the  narcotine,  if  any,  will  be  found  in  the  residue.  The  amount 
of  this  residue,  and  the  intensity  of  its  color  under  action  of 
concentrated  sulphuric  acid,  furnish  comparative  evidences  of 
the  quantity,  or  comparative  quantities,  of  narcotine  as  an  im- 
purity in  the  morphine  salt. 

NAKCOTINE. — C22H23NO7  =  413.  (For  structure  see  p.  361.) 
— Occurs  in  opium,  in  very  variable  proportions,  from  1.3$  to 
10.9$.  Some  samples  of  French  opium  do  not  contain  any  re- 
coverable by  ordinary  methods.  T.  and  H.  SMITH  found  an  al- 
kaloid, aconettine,  in  the  roots  of  Aconitwni  Napellus,  which 
they  thought  was  identical  with  narcotine. 

Narcotine  is  characterized  by  its  deportment  with  pure  sul- 
phuric acid,  and  with  sulphuric  and  nitric  acids  (d) ;  distin- 
guished and  separated  from  morphine  by  its  solubility  in  ether 
(c),  even  from  feebly  acidulous  solutions.  It  is  estimated  gravi- 
metrically  or  by  Mayer's  solution  (f).  Separation  from  opium 
(0),  from  morphine,  under  Morphine  (g\  p.  386. 

a. — Crystallizes  from  alcohol  or  ether  in  colorless,  transpa- 
rent, orthorhombic  prisms,  or  in  groups  of  needles,  which  melt 
at  170°  C.,  solidifying  again  at  130°,  crystalline  if  cooled  slowly, 
otherwise  amorphous.  Above  200°  C.  it  splits  into  meconine  and 
cotarniiie  (MATTHIESSEN  and  WRIGHT). 

It  is  heavier  than  water,  odorless,  and  forms  salts  of  feeble 
combining  force,  mostly  amorphous,  and  acid  in  reaction.  The 
salts  are  soluble  in  water,  alcohol,  and  ether,  and  are  to  a  greater 
or  less  extent  decomposed  either  by  addition'  of  much  water  or 
(when  the  acid  is  a  volatile  one)  by  evaporating  the  solutions. 

b. — JSTarcotine  in  solution  is  bitter,  when  free  nearly  taste- 
less. It  acts  as  a  narcotic  poison,  though  only  in  large  doses 
(from  1.5  to  3.0  grams). 

c. — Narcotine  is  soluble  in  about  25000  parts  cold  and  7000 
parts  boiling  water ;  when  freshly  precipitated  by  ammonia,  in 
about  1500  parts  cold  and  600  parts  boiling  water ;  in  120  parts 
cold  and  20-24  parts  boiling  alcohol  (96$) ;  in  126  parts  cold 
and  48  parts  boiling  ether  (sp.  gr.  0.735) ;  in  60  parts  acetic 
ether;  in  2.7  parts  chloroform  ;  in  300  parts  amylic  alcohol ;  in 
22  parts  benzene ;  slightly  soluble  in  petroleum  benzin,  which 


388  OPIUM  ALKALOIDS. 

takes  up  only  a  trace  from   alkaline  solutions  (DRAGENDORFF). 
Chloroform  removes  it  from  acid  solutions. 

d. — The  alkaline  hydrates,  carbonates,  and  acid  carbo- 
nates precipitate  narcotine  (white,  crystalline,  insoluble  in  ex- 
cess of  precipitant).  Iodine  in  potassium  iodide  gives  a  pre- 
cipitate (brown),  potassio-mercuric  iodide  (white  amorphous), 
potassium  sulphocyanate  (amorphous).  The  other  alkaloid 
reagents  also  precipitate  narcotine,  the  precipitates  not  being 
characteristic.  Concentrated  sulphuric  acid  dissolves  narcotine, 
at  first  colorless,  becoming  yellow.  Upon  heating  gently  the 
solution  becomes  orange-red,  then  violet  to  dark  blue  streaks 
appear,  and  finally  the  mixture  assumes  an  intense  violet-red 
color.  If  the  heat  be  stopped  before  the  violet-red  color  ap- 
pears, the  solution  becomes  cherry-red  on  cooling  (HUSEMANN). 
If  a  drop  of  nitric  acid  be  added  to  a  solution  of  narcotine  in 
sulphuric  acid,  a  red  color  appears.  FROEHDE'S  reagent  dissolves 
narcotine  with  green  color,  becoming  brown,  finally  reddish. 
Concentrated  nitric  acid  dissolves  it  with  a  yellow  color. — In 
the  oxidation  of  narcotine,  by  nitric  acid  or  acid  chromate,  or  by 
permanganate,  cotarnine  and  opianic  acid  are  formed  as  follows : 
€22H23NO7  +  O  =  C12H13NO3  (cotarnine)  +C10H10O5  (opianic 
-acid).1 

e. — Narcotine  is  obtained,  in  greater  part,  from  the  residue 
after  treating  opium  with  water  (see  Morphine,  /),  by  extract- 
ing with  dilute  hydrochloric  acid,  precipitating  with  sodium 
acid  carbonate,  extracting  the  precipitate  with  boiling  80$  alco- 
hol, and  crystallizing  out.  It  is  then  purified  by  washing  with 
cold  alcohol  and  recrystallizing  from  boiling  alcohol.  Narcotine 
may  also  be  extracted  from  opium  by  means  of  ether,  and  crys- 
tallizes out  on  concentrating  the  ether  solution.  For  the  sepa- 
ration of  narcotine  from  morphine  see  under  Morphine,  ^, 
p.  386. 

f. — Narcotine  can  be  estimated  gravimetrically.  Also  by 
means  of  Mayer's  solution,  of  which  1  c.c.  precipitates  0.0213 
gram  of  narcotine. 

CODEINE. — C18H21NO3  =  299.  (Structure,  p.  361.)  In  opium, 
from  0.1  to  1  per  cent. 

1  WOHLKR,  1844:  Ann.  Ghent.  Phar.,  50,  19.  MATTHIESSEN  and  FOSTER, 
1860:  Ann.  Chem.  Phar.,  Supplement  B,  i,  330  ;  Jour.  Chem.  Soc.  [2]  i, 
342.  ANDERSON,  Ed.  Phil.  Trans. ,  20  [3]  359  ;  Jour.  Chem.  Soc. ,  5,  266. 
Also  see  "  Watts's  Diet./'  ii.  89. 


CODEINE.  389 

Codeine  is  characterized  by  its  solubilities  in  water,  benzene, 
and  ether  (<?),  whereby  it  is  distinguished  and  separated  from 
morphine  and  from  narcotine.  Its  bright  color-reactions  with 
sulphuric  acid,  alone  and  with  the  oxidizing  agents  (d),  though 
somewhat  distinctive  from  other  alkaloids  in  general,  are  yet  in 
a  near  resemblance  to  the  parallel  reactions  of  morphine  and  of 
narcotine.  Tests  for  purity  are  presented  (g)  on  p.  390. 

a. — Codeine  crystallizes  from  its  solution  in  absolute  ether 
in  small,  colorless,  anhydrous  crystals.  In  presence  of  water  it 
crystallizes  in  large  octahedra  and  prisms  of  the  orthorhombic 
system  having  the  composition  C18H21NO3.H2O.  These  be- 
come anhydrous  at  100°  C.,  and  melt  to  an  oil-like  liquid  in  boil- 
ing water.  The  anhydrous  alkaloid  melts  at  150°  C.,  and  solidifies 
to  a  crystalline  mass  on  cooling.  It  rotates  the  plane  of  polari- 
zation to  the  left.  It  has  a  strongly  alkaline  reaction.  It  pre- 
cipitates salts  of  some  of  the  heWy  metals.  Its  salts  (mostly 
crystallizable)  are  very  bitter  and  almost  insoluble  in  ether.  The 
hydrochloride,  C18H21NO3 .  HC1 .  2H2O,  becomes  anhydrous  at 
121°  C.  It  is  soluble  in  less  than  one  part  of  boiling  water,  in  20 
parts  of  cold  water. 

b. — Codeine  is  odorless,  slightly  bitter,  and  resembles  mor- 
phine in  its  physiological  action.  The  dose  is  from  0.5  to  1  0 
grain  (0  032  to  0.065  gram). 

G. — Codeine  is  soluble  in  80  parts  cold  (15°  C.)  and  17  parts 
boiling  water ;  readily  soluble  in  alcohol,  ether,  and  chloroform  ; 
in  7  parts  amyl  alcohol ;  in  10  parts  benzene  ;  almost  insoluble  in 
petroleum  benzin.  Chloroform  extracts  it  most  easily  from  alka- 
line solutions.  It  has  an  alkaline  reaction,  and  neutralizes  acids. 

d. —  Ammonia  precipitates  codeine  from  solutions  of  its  salts 
only  after  standing  some  time,  and  then  not  completely.  Potas- 
sium hydrate  precipitates  codeine  (partly  soluble  in  excess). 
The  alkaline  carbonates  cause  no  precipitate  in  the  cold. 
Iodine  in  potassium  iodide  precipitates  it  (brown),  potas- 
sio-mercuric  iodide  (white),  potassio-cadmic  iodide  (white), 
phosphomolybdic  acid  (yellow-brown),  tannic  acid  (even  from 
very  dilute  solutions,  white,  soluble  in  hydrochloric  acid),  mer- 
curic chloride  (crystalline),  platinic  chloride  (from  concentrated 
solutions,  yellow),  gold  chloride  (from  concentrated  solutions, 
brown),  potassium  sulphocyanate  (colorless,  crystalline,  dissolv- 
ing on  warming).  Concentrated  sulphuric  acid  dissolves  codeine 
without  color,  becoming  blue  on  warming  or  after  standing  seve- 
ral days,  sooner  if  there  be  a  trace  of  nitric  acid  present  or  if  a 
trace  of  ferric  salt  be  added.  Concentrated  nitric  acid  dissolves 


3QO  OPIUM  ALKALOIDS. 

it  with  orange-yellow  color.  Froehde's  reagent  dissolves  it  with 
dirty  green  color,  becoming  blue.  If  to  a  small  portion  of  co- 
deine, in  a  watch-glass,  there  be  added  two  drops  of  sodium 
hypochlorite  solution,  and  then  four  drops  of  concentrated  sul- 
phuric acid,  after  mixing  with  a  glass  rod  a  line  blue  color  is  ob- 
tained (RABY,  1885). 

g. — "  If  codeine  be  added  to  nitric  acid  of  sp.  gr.  1.200,  it 
will  dissolve  to  a  yellow  liquid  which  should  not  become  red 
(difference  from  and  absence  of  morphine)." — U.  S.  Ph. 

APOMORPHINE. — C17HrrN"O2  =  267.  A  product  of  morphine 
by  the  action  of  concentrated  hydrochloric  acid  at  140°-150°  C., 
or  with  zinc  chloride  at  110°  C. :  'C17II19KO3=C17H17IsrO2+H2O. 
A  product  of  codeine,  by  intermediate  formation  of  chlorocodid, 
C18H20C1NO2,  which  splits  into  CH3C1  and  C17H17NO2.— As  a 
hydrochloride,  in  use  in  medicine. 

Apomorphine  is  identified  by  the  bright  colors  assumed  by 
its  solutions  in  various  solvents  (c,  d),  and  the  green  color  soon 
taken  by  its  precipitate  as  free  alkaloid  (d) ;  also  by  color  tests 
(d).  It  may  be  separated  by  the  action  of  its  solvents  (c).  Its 

£r'dy,  in  the  hydrochloride,  is  tested,  as  regards  presence  of  its 
lomposition  products,  by  noting  the  color  of  its  solutions  (g). 
a. — When  pure,  in  snow-white,  crystalline  masses  ;  generally 
found   green-gray  or  gray- white;   and  by   exposure  to  the  air 
acquiring    greenish    and    grayish    tints.      The    Hydrochloride, 
C17H17NO2.HC1=  303.4,  is  in  "minute,  colorless,  or  grayish- 
white,  shining  crystals,  turning  greenish  on  exposure  to  light 
and  air  "  (U.  S.  Ph.)     A  "  white  or  gray-white  crystalline  pow- 
der," "  becoming  green  by  action  of  air  and  light "    (Ph.  Germ.) 
Oxidation  occurs  as  the  green  color  appears. 

b. — Apomorphine  and  its  salts  are  bitter  to  the  taste  and 
without  odor.  In  effect  upon  man,  a  prompt  and  non-irritant 
emetic.  Dangerous  and  even  fatal  symptoms  have  followed  the 
hypodermic  administration  of  one-sixth  of  a  grain.  Medicinally, 
to  an  adult,  -gV  to  TV  grain  (0.001  to  0.006  gram)  is  administered 
by  the  stomach.  The  Ph.  Germ,  maximum  dose  is  0.01  gram. 
With  animals,  convulsions  often  follow  administration. 

c. — Apomorphine,  a  free  base,  is  slightly  soluble  in  water, 
readily  soluble  in  alcohol,  ether,  chloroform,  or  benzene;  the 
aqueous  and  alcoholic  solutions  turn  greenish ;  the  solutions  in 
solvents  immiscible  in  water,  rose-purple  to  violet.  -  The  hydro- 
chloride  (see  a)  is  freely  soluble  in  water  or  alcohol,  the  solu- 
tions turning  green  on  boiling  or  on  standing.  In  ether  the  salt 
is  almost  insoluble.  The  hydrochloride  has  "  a  neutral  or  faintly 


ORGANIC  ANALYSIS.  391 

acid  reaction  "  (U.  S.  Ph.) ;  "  a  very  faint  acid  reaction  on  moist- 
ened litmus-paper"  (Br.  Ph.);  a  neutral  reaction  (Ph.  Germ.) — 
these  statements  concerning  the  degree  of  purity  of  the  salt. 

d. — The  alkali  hydrates  precipitate  apomorphine  from  solu- 
tions of  its  salts,  the  precipitate  dissolving  in  excess  of  either 
alkali  with  such  readiness  that  precipitation  is  not  easily  made  to 
appear.  The  alkali  solutions  turn  green.  Sodium  bicarbonate 
gives  a  precipitate,  only  slightly  dissolved  by  excess  of  the  re- 
agent, and  distinguished  by  turning  green  on  exposure.  Shaken 
up  with  chloroform,  the  precipitate  dissolves  in  this  solvent, 
which  separates  with  a  violet  to  blue  color.  Ether  or  benzene, 
used  in  the  same  way,  takes  a  purple  to  violet  color.  The  alka- 
line solution,  of  excess  of  alkali  hydrate,  turning  green  and 
finally  black,  imparts  red-purple  color  to  ether,  and  crimson  to 
blue  colors  to  chloroform,  benzene,  or  carbon  disulphide  (WRIGHT, 
1873). — Potassium  iodide  gives  a  white  precipitate,  soon  be- 
coming green  (WRIGHT)  ;  silver  nitrate,  a  white  precipitate, 
rapidly  turning  black  by  reduction  to  metallic  silver,  a  result 
obtained  at  once  if  ammonia  be  added. — Nitric  acid  gives  a 
blood-red  color ;  ferric  chloride  dilute  solution,  a  pink  or 
amethystine  color ;  iodine  in  potassium  iodide,  a  red  color. — 
Sulphuric  acid  gives  a  violet  to  brown  ;•  Froehde's  reagent,  a 
green  to  violet  color. — The  general  reagents  for  alkaloids  give 
precipitates  with  apomorphine  salts  in  solution. 

g. — The  watery  solution  of  the  salt  [hydroehloride]  should  be 
colorless  or  not  strongly  colored ;  if  a  solution  in  100  parts  of 
water  be  emerald-green,  the  article  should  be  rejected  (Ph. 
Germ.)  Respecting  purity,  also,  see  statements  as  to  the  reac- 
tion with  test -papers  (c). 

ORGANIC  ANALYSIS.—  The  analytical  chemistry  of 
carbon  compounds.  A  determination  of  the  chemical  compo- 
sition of  organic  materials. — Organic  substances,  in  their  chemi- 
cal character,  are  known  simply  as  compounds  of  carbon  and  as 
derivatives  of  the  hydrocarbons,  and  are  not  sharply  separated 
from  inorganic  substances.  In  the  statements  of  chemistry  the 
term  organic  has  no  fixed  relation  to  vitality,  or  to  the  products 
of  living  bodies,  or  to  organized  structure  of  an  anatomical  form. 
Matter  is  made  up  of  molecules,  whether  it  be  organic  matter  or 
not ;  and  the  molecule  is  strictly  a  chemical  product,  whether  it 
contain  carbon  or  not.1 

1  Inasmuch  as  the  molecule  is  the  final  product  of  chemical  action,  it  fol- 
lows that  the  cell  is  not  built  up  into  an  anatomical  form,  from  the  collection  of 
its  constituent  molecules,  by  virtue  of  chemical  action  as  a  typical  force.  In 


392  ORGANIC  ANALYSIS. 

Any  operation  partly  or  wholly  to  determine  the  chemical 
composition  of  a  portion  of  organic  matter  may  be  termed  an 
operation  of  organic  analysis.  Such  operations  widely  differ 
from  each  other  in  scope  and  extent,  from  a  simple  qualitative 
test  of  the  presence  of  a  given  carbon  compound  to  an  elaborate 
scheme  for  separating  and  estimating  all  the  distinct  substances 
in  a  complex  mixture,  and  then  determining  the  elemental  struc- 
ture of  certain  of  these  substances. 

If  a  distinct  chemical  compound  have  been  already  obtained 
in  strict  purity,  the  determination  of  its  elemental  composition 
and  structure  is  one  of  the  first  and  most  important  of  the 
studies  necessary  to  its  chemical  acquaintance.  For  carbon  com- 
pounds the  centesimal  figures  of  elemental  composition  are  ob- 
tained by  operations  of  "elementary  organic  analysis"  or  "•  ulti- 
mate organic  analysis,"  as  described  on  pages  198  to  238  of  this 
work.  Beyond  the  finding  of  true  centesimal  figures,  and  out- 
side of  analytical  chemistry  as  a  division  of  chemical  work,  there 
remain  the  important  tasks  of  learning  the  real  molecular  weight 
and  the  actual  molecular  structure  of  the  substance  under  inves- 
tigation. Studies  of  structure  were  referred  to,  in  consideration 
of  rational  chemical  formulae,  on  page  238,  and  require  the  same 
breadth  and  faithfulness  of  original  research  that  are  necessary, 
for  example,  in  determinations  of  atomic  weights.  But  mere  ul- 
timate organic  analyses  are  routine  operations,  making  no  greater 
demand  than  that  of  exact  execution  of  well-worn  analytical 
methods.  Certainly  the  estimation  of  the  elements  in  a  given 
carbon  compound  already  separated  in  purity  is  a  very  narrow 
task  when  compared  with  that  of  the  determination  and  separa- 
tion of  the  several  carbon  compounds  in  a  given  portion  of  or- 
ganic material. 

The  proper  place  which  "  elementary  analysis  "  holds  in  ana- 
lytical chemistry,  in  comparison  with  that  of  "  proximate  analy- 
sis," will  appear  in  a  true  light  if  we  contrast  the  one  kind  of 
analytical  work  with  the  other,  when  applied  to  common  inor- 
ganic materials.  Thus,  there  are  at  least  eight  sulphur  acids  con- 
sisting each  of  sulphur  and  hydrogen  and  oxygen,  besides  com- 
pounds of  sulphur  with  hydrogen,  sulphur  with  oxygen,  sulphur 
with  halogens,  and  numerous  other  "  inorganic  "  compounds  of 
sulphur.  The  percentage  of  sulphur  in  each  of  these  compounds 
was  long  since  established  to  within  narrow  limits  of  error,  and 
their  "  ultimate  analysis  "  for  sulphur  is  now  required  only  as  an 

the  organization  of  the  cell,  chemism  can  exert  no  other  power  than  that  of  a 
"  correlative  force,"  acting  in  such  a  way  as  that  by  which  heat  enables  certain 
chemical  combinations  to  take  place. 


ORGANIC  ANALYSIS.  393 

infrequent  resort  in  indirect  methods  of  estimating  sulphur 
compounds.  Qualitative  and  quantitative  analyses  for  sulphu- 
ric acid  and  for  other  common  compounds  of  sulphur  are  in 
constant  demand,  and  are  made  with  confidence,  although  we 
have  no  general  analytical  scheme  for  all  sulphur  compounds. 
Determinations  of  the  presence  and  proportion  of  sulphuric 
acid  are  not  spoken  of  as  operations  in  "proximate  analysis." 
Neither  is  the  estimation  of  acetic  acid  often  referred  to  as  a 
"  proximate  organic  analysis."  The  term  "  proximate "  has 
been  carefully  defined,  over  and  over  again,  to  specify  a  cer- 
tain kind  of  analyses,  but  in  its  principal  use  by  chemists  the 
term  seems  to  have  belonged  mainly  to  such  analytical  undertak- 
ings as  have  been  quite  remote  from  realization.  With  this 
distant  apprehension  on  the  part  of  chemists  it  is  not  strange  that 
laymen  should  forget  what  the  precise  difference  is  between  u  prox- 
imate "  and  "  approximate  "  determinations  in  the  laboratory. 

To  determine  and  to  separate  chemical  compounds  as  they 
exist  in  the  material  under  inquiry,  to  assort  the  molecules  and 
to  ascertain  their  structure  without  permitting  any  changes  in 
them  to  elude  observation,  is  the  end  to  be  reached  in  analytical 
chemistry,  whether  of  inorganic  or  organic  substances,  whether 
for  qualitative  or  quantitative  statements,  and  whether  the  de- 
sired percentages  be  those  of  compounds  in  a  given  mixture  or 
those  of  elements  in  a  given  compound.  Divisions  of  analysis 
for  inorganic  and  organic  articles,  or  for  qualitative  and  quanti- 
tative purposes,  are  only  divisions  of  labor  designed  for  the  con- 
venience of  chemists,  and  are  sometimes  an  occasion  of  embar- 
rassment and  delay.  Like  the  differences  between  inorganic  and 
organic  general  chemistry,  the  distinctions  between  inorganic  and 
organic  analysis  have  been  overstated,  quite  to  the  discourage- 
ment of  learners  and  to  the  misleading  of  scientific  inquiry. 

In  any  so-called  branch  of  chemical  analysis  the  operator 
may  resort  to  separation  by  physical  state  without  chemical 
change,  or  to  reactions  of  substitution,  addition,  or  disunion  ;  but 
whatever  the  resource,  it  is  required  to  trace  the  relation  be- 
tween the  external  deportment  and  the  molecular  structure  of 
substances,  and  to  make  acquaintance  with  the  character  of  the 
compounds  under  treatment. 

PALMITIC  ACID.  See  FATS  AND  OILS,  p.  244. 
PAPAVERINE.  See  OPIUM  ALKALOIDS,  p.  359. 
PAYTINE.  See  CINCHONA  ALKALOIDS,  p.  92. 


394 


PHENOL. 


PHENOL.— C6H5OH  =  91.  Hydroxylbenzene.— The  first 
member  of  a  series  of  PHENOLS,  CnH2n_7OH,  a  series  of  mono- 
hydroxyl  benzenes.  Phenols  have  a  structure  as  though  derived 
from  the  hydrocarbons,  benzene,  C6II6  ;  toluene,  C7H8,  etc. — by 
substituting  OH  for  H  in  the  mono  hydroxyl  benzenes,  2OH  for 
2H  in  the  di-hydroxyl  benzenes,  etc.1 

Phenol  may  be  obtained  by  the  destructive  distillation  of 
resins  and  many  other  organic  substances.  It  is  formed  in  the 
dry  distillation  of  salicylic  acid,  more  readily  if  lime  be  added : 
C6H4 .  OH .  COgH  =  C6H6O  +  CO? .  The  urine  of  various  ani- 
mals contains  phenol,  and  it  is  liable  to  occur  in  the  urine 
of  man.  Certain  albuminoid  decompositions,  or  putrefactions, 
generate  phenol.  It  often  appears  in  the  distillates  from  wood- 
tar,  making  an  impurity,  or  less  valued  constituent,  of  true  wood- 
tar  creosote,  which  contains  phenols  of  another  series.  But  the 
phenol  in  use  comes  from  no  other  source  than  the  distillation  of 
coal-tar,  and  bears  the 'name  of  Carbolic  Acid.  The  making  of 
this  article  has  been  an  industry  since  about  1860.  Crude  car- 
bolic acid  contains  phenol  with  the  cresols  and  some  of  the  xyle- 
nols  of  the  following  list.  Best-grade  carbolic  acid  is  nearly 
pure  phenol.  The  article  sold  as  "  cresylic  acid,"  of  variable 
composition,  contains  cresols  and  may  include  xylenols. 


Melting.* 

Boiling.* 

Phenol,  C6H5  .  OH  =                       C6H6O 

42°  C. 

184°  C. 

Cresols,  C6H4.CH3  OH  =             C7H8O 

Orthocresol,  1     2 

31° 

186° 

Metacresol,    1     3 

liquid 

194°-200° 

Paracresol,    1     4 

36° 

198° 

Xylenols,  C6H3  .  CH3  CH3  .  OH  =  C8H10O 

Orthoxylenol,  124 

61° 

225° 

Metaxylenol,    134 

liquid 

211° 

Metaxylenol,    132 

74° 

212° 

Paraxylenol,    142 

75° 

213° 

'KEKULB,  1865:  "Organ.  Chem.,"  iii.   (1882),  1,  12;  "Substitution 
ducts,"   25.     "  Watts's  Dictionary,"  vii.  924  (ARMSTRONG),  132.     Ladenburg's 
"  Handworterbuch."     Remsen's  ""  Organic  Chemistry,"  269,  233. 

2  The  melting  and  boiling  points  of  the  isomeric  cresols  and  xylenols  have 
been  ascertained,  mainly,  from  the  artificial  compounds.  The  isomers  have 
not  been  separated  in  purity  from  coal-tar  distillates.  It  is  not  known  to  what 
extent  xylenols  and  the  several  cresols  occur  in  crude  carbolic  acids  and  in 


PHENOL. 


395 


In  the  distillation  of  coal-tar  the  distillate  is  received  in  frac- 
tions limited  usually  by  boiling  points,  sometimes  by  volume- 
quantities,  and  generally  in  part  by  specific  gravities,  with  regard 
also  to  periods  of  distillation.  The  number  and  limits  of  the 
fractions  of  distillate  have  varied  with  the  progress  of  the  in- 
dustry and  with  local  customs  and  special  purposes.1  After  va 
porization  of  the  water  and  ammonia,  under  name  of  the  "  first 
runnings"  or  "crude  naphtha,''  a  "  break  "  occurs,  after  which 
distillation  recommences  at  105°  to  110°  C.  Beginning  at  this 
point,  the  first  fraction  is  almost  everywhere  named  u  light  oil," 
and  contains  the  hydrocarbons  of  the  benzene  series.  Formerly 
the  distillate  was  generally  received  as  "  light  oil "  until  a  por- 
tion ceased  to  float  on  water  (sp.  gr.  1.0),  when  the  boiling  point 
is  about  210°  C.  [LUNGE].  At  present,  in  many  places  where 
carbolic  acid  is  an  object,  the  "  light  oil "  is  cut  oif  at  165°-170° 
C. ;  and  a  fraction  of  "  middle  oils,"  for  carbolic  acid  and  naph- 
thalene, is  received  up  to  230°  C.  "Light  oil,"  if  carried  to 
210° C.,  contains  a  good  deal  of  carbolic  acid;  if  cut  off  at  170° 
C.  it  contains  but  little.  But  after  a  "  light  oil "  is  distilled  up  to 
210° C.,  a  fraction  named  "carbolic  oil"  is  received,  up  to  240° 
C.,  as  a  source  of  carbolic  acid.  The  term  "creosote  oil" 
("  heavy  oil ")  is  very  generally  applied  to  a  fraction  taken  either 
after  "'carbolic  oil"  or  "middle  oil,"  and  cut  off  at  270° C. 
Carbolic  acid  is  not  ma<'e  from  "creosote  oil,"  or  from  any 
distillate  above  240°  C.,  but  "  creosote  oil "  contains  unknown 
quantities  of  cresols  and  xylenols.  It  is  used  entire,  for  lubri- 
cating, pickling  timbers,  etc.,  etc.,  and  has  not  gained  much  cre- 
dit for  antiseptic  power.  Above  270°  C.  a  final  distillate  named 
"  anthracene  oil "  ("  green  oil "  or  "  red  oil  ")  is  now  generally 
obtained  as  a  source  of  anthracene,  a  product  of  great  value. 
Formerly  all  distillate  after  "light  oil"  was  taken  in  one  por- 
tion as  "dead  oil";  and  all  the  fractions  after  "light  oil,"  sink- 
ing in  water,  may  now  be  classed  as  "  dead  oils."  If  the  distil- 
lation be  stopped  when  "  light  oil"  is  received,  the  retort-resid-ue 
is  called  "  asphalt  "  ;  if  "  dead  oils  "  are  distilled,  the  residue  is 
"  soft  pitch  "  or  "  hard  pitch,"  according  to  the  persistence  of 
distillation.  Carbolic  acid,  then,  is  obtained  from  distillates  be- 
low 240°  C.,  arid  mainly  from  portions  taken  after  the  "  light 

cresylic  acid.  On  artificial  xylenols,  JACOBSEN,  1878  :  Jour.  Chem.  Soc.,  34, 
411.  On  cresols,  OPPENHEIM  and  PFAFF,  "  Watts's  Diet.,"  viii.  581.  The  state- 
ments that  there  is  one  liquid  cresol  and  one  liquid  xylol  are  of  interest  in 
view  of  the  fact  that  "  cresylic  acid  "  also  remains  liquid  at  low  temperatures. 
Paracresol  is  found  to  have  a  more  powerful  local  ancesthetic  effect  than  carbo- 
lic acid  (McNEiLL,  188»i). 

1  On  this  subject  see  Lunge's  "  Coal  tar  Distillation,"  1882. 


396  PHENOL. 

oil,"  though  some  carbolic  acid  is  saved  in  purifying  the  ben- 
zoles of  "  light  oil." 

The  treatment  of  a  distillate  for  carbolic  acid  usually  begins 
with  an  agitation  with  caustic  soda  solution,  more  or  less  dilute 
(12#  to  40^  of  hydroxide),  the  alkaline  solution  of  the  phenols 
being  afterward  acidulated  to  separate  Crude  Carbolic  Acid, 
which  rises  as  a  liquid  layer.  Strong  alkalies  dissolve  non- 
phenols  ;  weak  alkalies  fail  to  dissolve  all  the  cresylic  acid. 
Acidulation  is  done  by  sulphuric  acid  (mostly  in  lead- lined  ves- 
sels), by  hydrochloric  acid,  and  with  best  results  by  carbonic 
acid.  Crude  carbolic  acid  is  apt  to  contain  sulphuric  or  hydro- 
chloric acid.  The  manufacturer  sometimes  improves  it  by  wash- 
ing with  a  little  water  or  by  distilling  it.  Crude  carbolic  acid 
should  have  a  specific  gravity  of  1.050-1.065  at  15.5°  C.  (AL- 
LEN). Watson  Smith  found  samples  of  it  to  yield  61  \  to  62£  per 
cent,  of  carbolic  acids  of  a  grade  to  solidify  at  15°  to  18°  C.,  and 
12  to  15  per  cent,  of  water.  Methods  of  valuation  of  crude  car- 
bolic acid  are  noted  under  Separations  (p.  401)  and  Quantitative 
(p.  404). 

All  the  phenols  both  of  crude  carbolic  acid  and  of  wood-tar 
creosote  agree  in  giving,  among  other  reactions,  deep-colored 
nitro-acids  with  nitric  acid  ;  pale'colored  bromo-compounds  with 
bromine-water ;  soluble  sulphonic  acids  by  standing  with  con- 
centrated sulphuric  acid ;  and  feebly  chemical  solutions  with 
alkali  and  water,  from  which  they  are  separated  by  acidulating. 
Definite,  crystallizable  salts  are  easily  obtained  from  nitro-phenic 
acid,  likewise  from  phenolsulphonic  acid,  but  the  alkali  phenols, 
or  "  carbolates,"  are  not  easily  obtained  in  purity. 

CARBOLIC  ACID. —  Carbolsdure.  Crystallized  carbolic  acid. 
Phenol  of  approximate  purity  obtained  from  coal-tar.  Recog- 
nized by  its  sensible  properties  (0,  b)  ;  identified  by  reactions 
with  bromine,  ferric  chloride,  nitric  acid,  etc.  (d) ;  distinguished 
from  Creosote  by  its  behavior  with  ferric  chloride,  albumen,  col- 
lodion, glycerin  (d) ;  separated  by  distillation,  solvents,  etc.  (e 
and  c) ;  estimated,  volumetrically  or  gravimetrically,  by  bromine 
(y,  p.  404).  For  chemical  relations  and  manufacture  see 
p.  395 ;  examination  respecting  purity  and  quality,  g  and  a  • 
Nitro-phenic  acid,  p.  398;  Sulphocarbolic  acid,  p.  405.  For 
separation  from  the  Urine,  p.  402 ;  in  Toxicology,  p.  402. 

a,  b. — Carbolic  acid  appears  in  a  crystalline  mass  of  inter- 
laced needles,  colorless,  or,  after  keeping,  faintly  pinkish,  with  a 
characteristic  and  aromatic  odor  (feebly  creosote-like — HAGEK), 


CARBOLIC  ACID.  397 

and  (when  diluted  with  much  water)  a  sweet  taste  with  a  burn- 
ing after-taste.  Only  the  imperfectly  purified  grades  have  an 
odor  like  that  of  creosote  (SQUIBB).  In  full  concentration  it  is 
caustic  to  the  skin,  which  it  whitens,  and  gives  a  sensation  of 
numbness,  acting  as  a  local  anaesthetic  (MoNEiLL,  1886).  Inter- 
nally it  is  an  active  poison,  even  if  so  diluted  as  not  to  be  corro- 
sive, the  full  medicinal  dose  being  one  or  two  grains  It  is  neu- 
tral in  reaction.  From  solution  in  petroleum-ether  separate 
needle-form  crystals  of  phenol  are.  obtained.  In  presence  of 
water  crystals  can  be  formed  of  the  composition  2C6H6O .  H2O, 
equal  to  9.57  per  cent,  of  water  (CALVEKT,  1865).  The  best 
carbolic  acid  of  the  market  "contains  2  to  4  per  cent,  of  water, 
and  some  very  good  acid  contains  much  more  "  (SQUIBB,  1883). 
Phenol  crystallized  from  petroleum-ether  melts  at  44°  C.(111°F.) 
(FLUCKIGER  :  "Phar.  Chem.,"  280) ;  perfectly  pure  phenol  at 
42. 2°  C.,  at  43.2°  C.  (SCHERING,  HAGER).  CALVERT  found  the 
hydrate  to  melt  at  16.6°  C.  (62°  F.)  The  congealing  point  is  the 
more  constant  criterion,  and,  when  incited,  good  carbolic  acid  of 
the  market  was  found  to  congeal  at  from  29.4°  to  39.5°  C. ;  also, 
addition  of  2  per  cent,  of  water  lowered  the  congealing  point 
7.9°  C.  (SQUIBB:  Ephemeris*  i.  305).  Carbolic  acid  melts  at  35° 
to  44°  C.  (Ph.  Germ.,  1882),  "at  36°  to  42°  C.  (96.8°  to 
107.6°  F.),  and  boils  at  181°  to  186°  C.  (357.8°  to  366.8°  F.),  the 
higher  melting  and  lower  boiling  points  being  those  of  the  pure 
and  anhydrous  acid"  (U.  S.  Ph.,.1880).  Phenol  boils  at  187°  to 
188°  C.  (LAURENT,  1841).  A  fine  specimen  of  carbolic  acid, 
congealing  at  38.5°  C.,  boiled  first  at  170°  C.,  later  at  183°  C. ; 
another  sample,  first  at  173°  C.,  later  at  186.2°  C.  (SQUIBB,  where 
last  quoted).  Both  Cresol  and  Creosote  remain  liquid  when 
exposed  to  a  freezing  mixture  (ALLEN). — The  specific  gravity  of 
phenol  is  1.065  at  18°  C.  (LAURENT,  1841),  1.0627  (SERUGHAM). 
"When  melted  to  a  liquid  the  specific  gravity  of  carbolic  acid  is 
1.060  (Ph.  Germ.) 

c. — It  has  been  a  general  statement  that  phenol  is  soluble  in 
20  parts  of  water,  a  statement  applied  to  carbolic  acid  by  the  U. 
S.  Ph.r  1880,  and  Ph.  Germ.,  1882.  ALLEN  '  found  the  acid 
(Cal  vert's  No.  1)  to  dissolve  in  10.7  parts  by  weight  of  water  for 
1  part  of  absolute  acid.  Likewise,  it  has  been  a  frequent  state- 
ment that  carbolic  acid  dissolves  only  one-twentieth  (5$)  of  its 
weight  of  water,  but  according  to  Allen  it  dissolves  about  27  per 
cent,  of  water  (nearly  2H2O).  With  elevation  of  temperature  a 
larger  proportion  of  water  can  be  held  in  solution,  the  mixture 

1 1878:  Analyst,  3,  320;  Jour.  Chem.  Soc.,  36,  182. 


398  PHENOL. 

becoming  turbid  when  cooled.  A  permanent  liquid  state  is  ob- 
tained by  adding  5  per  cent,  of  water,  and  this  addition,  or  one 
of  a  fluid-ounce  of  water  to  a  pound  of  the  crystals,  is  usually 
adopted  in  dispensing.  Cresols  are  said  to  dissolve  in  about  31 
parts  of  water  (?)  The  alkalies  with  water  dissolve  carbolic  acid 
freely,  but  on  neutralizing  precipitation  occurs,  and  very  little 
phenol  is  dissolved  in  a  saturated  solution  of  common  salt1  Car- 
bolic acid  is  soluble  in  all  proportions  of  alcohol  and  of  glycerin, 
and  freely  soluble  in  ether,  chloroform,  benzene,  carbon  disul- 
phide,  volatile  oils,  and  in  fixed  oils,  water,  if  present,  being 
partly  separated  by  solvents  not  miscible  with  it.  Petroleum 
benzin  dissolves  but  little  carbolic  acid  in  the  cold. 

d. — Nitric  acid  reacts  upon  the  phenols,  violently  unless 
diluted,  producing  yellow  to  brown  mtro-compounds,  with 
escape  of  brown  nitric  oxide  vapors.  With  phenol  proper  it 
yields  successive  nitro-phenols,  the  final  product  being 
C6H2(NO2)3OH,  tri-nitrophenic  or  picric  acid.  The  color  is 
intensified  by  neutralizing  with  potash,  and  the  potassium  tri- 
nitrophenate  is  sparingly  soluble  in  water,  less  soluble  in  alcohol, 
and  crystallizes  in  bright  yellow  needles.  Some  analysts  add  to 
the  liquid  to  be  tested  an  equal  volume  of  sulphuric  acid  (not 
diluted)  and  then  a  minute  fragment  of  potassium  nitrate.  So- 
lution of  mercuric  nitrate  with  a  trace  of  nitrous  acid  gives  the 
nitric  acid  reaction  visible  in  dilution  of  the  phenol  to  150000  or 
200000  parts ;  Millon's  reagent  reveals  phenol  in  dilution  to 
2000000  parts,  in  20  c.c.  of  solution  (0.00001  gram  phenol) 
(ALMEN,  1878).  PICKIC  ACID  has  a  very  bitter  taste,  colors  the 
skin  and  fabrics  of  nitrogenous  composition  with  special  intensi- 
ty, acts  as  an  explosive  both  of  itself  and  with  reducing  agents, 
forms  true  salts  with  bases  in  general,  and  gives  constant  pre- 
cipitates in  solutions  of  the  alkaloids. 

Bromine-water,  with  solution  of  carbolic  acid,  gives  a  curdy 
or  crystalline,  whitish  precipitate,  tribromophenol,  C6H2Br3OH, 
soluble  in  excess  of  the  phenol,  but  permanent  upon  addition  of 
enough  of  the  reagent,  soluble  in  alcohol,  ether,  carbon  disul- 
phide,  etc.,  and  in  alkalies.  The  test  is  very  delicate,  but  in  very 
dilute  solutions  several  hours  should  be  given  for  the  formation 
of  the  crystalline  precipUate,  when  one  part  of  phenol  in  57100 

1  Dry  phenol  is  soluble  in  an  equal  volume  of  9  per  cent,  soda  solution. 
With  addition  of  water,  up  to  7  volumes,  the  liquid  remains  clear,  but  is  pre- 
cipitated by  8  volumes  of  water.  Dry  "  cresol "  is  soluble  in  an  equal  volume 
of  the  9  per  cent,  soda,  but  with  addition  of  the  soda  to  3^  volumes  a  precipi- 
tate occurs.  Creosote  requires  at  least  2  volumes  of  the  9  per  cent,  soda  to  dis- 
solve it. — ALLEN. 


CARBOLIC  ACID.  399 

parts  of  solution  is  revealed  (LANDOLT,  1871),  stellated  needles 
appearing  under  the  microscope.  Corresponding  precipitates,  of 
nearly  the  same  appearance,  are  given  by  the  homologues  of 
phenol,  by  aniline  and  its  homologues,  by  the  phenols  of  wood- 
tar  creosote,  by  certain  alkaloids,  arid  by  other  organic  substances. 
"With  "  cresylic  acid,"  or  crude  carbolic  acid,  the  precipitate  is 
amorphous  and  soft.1 

Ferric  chloride,  as  free  from  hydrochloric  acid  as  possible, 
in  solution  with  phenol  gives  a  tine  violet-blue  color.  Limit  of 
dilution  for  this  test,  1  part  in  3000  parts  (ALMEN,  1878).  Acids 
and  some  neutral  salts  interfere.  u  On  adding  to  10  c.c.  of  a 
one  per  cent,  aqueous  solution  of  carbolic  acid  one  drop  of  test 
solution  of  ferric  chloride,  the  liquid  acquires  a  violet-blue  color 
which  is  permanent  (the  color  thus  caused  by  Creosote  rapidly 
changing  to  greenish  and  brown,  with  formation,  usually,  of  a 
brown  precipitate) "  (U.  S.  Ph.)  But  in  more  concentrated  solu- 
tions this  test  does  not  clearly  distinguish  creosote  from  carbolic 
acid.  Various  organic  compounds,  and  according  to  SCHIFF  all 
compounds  containing  phenol-hydroxyl,2  give  violet  to  blue  colors 
with  ferric  salts. 

1  LANDOLT'S  original  report  upon  this  reaction,  both  in  its  qualitative  and 
its  gravimetric  uses,  is  full  and  satisfactory.  1871:  Ber.  d.  chem.  Ges.,  4,  770; 
Zeitsch.  anal.  Chem.,  n,  93;  Chem.  News,  24,  217.  Of  substances  giving  pre- 
cipitates with  bromine- water,  in  solutions  not  too  dilute,  Landolt  mentions 
quinine,  quinidine,  cinchonine,  strychnine,  and  narcotine,  all  giving  yellow  or 
orange  precipitates,  soluble  in  hydrochloric  acid,  but  insoluble  in  alkalies  [a 
distinction  from  phenol].  As  not  giving  precipitates  in  dilute  solutions,  there 
are  named  gallic  acid,  pyrogallol,  picric  acid,  bitter-almond  oil,  amygdalin, 
caffeine,  brucine,  and  hippuric  acid.  Morphine  gives  a  white  precipitate,  soon 
dissolving.  WORMLEY,  in  "Microchemistryof  Poisons,"  treats  of  Bromine  in  so- 
lution of  Hydrobromic  acid  as  a  reagent  for  alkaloids,  causing  crystalline  pre- 
cipitates with  the  greater  number  of  them. 

"That  is,  all  phenols,  and  all  derivatives  of  phenols  which  still  retain  one 
or  more  of  the  OH  of  phenols,  give  an  iron-bluing  reaction.  Schiff  enumerates, 
as  giving  blue  colors,  tannins,  gallic  acid,  pyrogallol,  other  tannin  derivatives, 
arbutin;  as  giving  violet  colors,  phenols,  salicylic  acid,  creosote,  salicylic  al- 
dehyde (oil  of  spircea),  methyl  salicylate  (C6H4.OH.C02CH3),  saligenm,  phe- 
nolsulphonic  acid  (CBH4.0H.Sp3H),  etc.;  giving  green  colors,  many  tannins, 
aesculetin,  etc.:  red  and  red-violet  colors,  phloridzin,  phloretin,  tyrosin,  and 
some  others.  Morphine  gives  the  blue  color,  and  CIIASTAING  (1881)  classes  it  as 
a  phenol.  The  reaction  is  not  given  with  nitro-compounds,  nor  with  com- 
pounds in  which  the  H  of  phenol  OH  is  displaced. — SCHIFF.  1871:  Ann.  Chem. 
Phar.,  159,  164;  Zeitsch.  anal.  Chem.,  10,  483;  Jour.  Chem.  Soc.,  24,  959.-— 
HAGER  states  that  the  following  substances  interfere  with  this  test:  organic 
acids,  mineral  acids,  phosphates,  acetates,  borax,  glycerin,  alcohol,  amyl  al- 
cohol.—Comparison  of  the  reaction  of  carbolic  acid,  salicylic  acid,  resorcin, 
antipyrine,  and  kairine,  with  ferric  chloride,  is  given  by  SCHWEISINGER.  1885: 
Archiv.  d.  Phar.,  222,  686;  Zeitsch.  anal.  Chem.,  24,  469.  Distinction  of  re- 
actions of  carbolic,  salicylic,  gallic,  and  tannic  acids,  with  ferric  salts,  HAGER, 
1880:  Ding.polyt.  Jour.,  235,  407;  Am.  Jour.  Phar.,  52,  204. 


4oo  PHENOL. 

Molybdic  acid  in  solution  in  concentrated  sulphuric  acid  is 
reduced  by  phenol  with  the  formation  of  a  purple  color.  The 
molybdic  acid  is  dissolved  in  ten  parts  of  the  sulphuric  acid,  a 
few" drops  of  this  reagent,  on  a  white  porcelain  surface,  are  cov- 
ered by  a  drop  of  the  solution  to  be  tested,  and,  after  a  momen- 
tary yellowish-brown  coloration,  the  purple  appears.  To  pro- 
mote the  reaction  the  liquid  may  be  slightly  warmed,  but  not 
above  53°  C.  The  reaction  is  a  delicate  one,  but  a  similar  color 
is  given  by  many  reducing  agents.  Creosote,  free  from  phenol 
and  pure,  gives  only  a  reddish-brown  tint  (E.  W.  DAVY).' 

Quinine  or  Cinchonidine,  as  Sulphate  or  Hydrochloride, 
yields  a  characteristic  crystalline  compound  with  phenol  (HESSE2). 
The  solution  to  be  tested  for  phenol  must  be  neutral.  To  this, 
while  hot,  a  neutral  solution  of  the  alkaloid  salt  is  added,  one 
drop  at  a  time,  and  so  sparingly  that  phenol  shall  be  in  excess,  if 
possible.  If  phenol  be  present  a  white  precipitate  appears, 
either  at  once  or  in  crystals  as  the  mixture  cools,  soluble  in  hot 
water,  sparingly  soluble  when  cold,  almost  insoluble  in  phenol- 
water,  easily  soluble  in  acids,  decomposed  by  alkalies,  crystal- 
lizable  from  alcohol.  With  quinine  sulphate  the  precipitate  is 
(C20H24N2O2)2H2SO4C6H6O.  The  dextro-rotary  cinchona  alka- 
loids, according  to  Hesse,  do  not  form  these  crystallizable  phe- 
nolo-compounds. 

Chlorate  of  Potassium  may  be  used  for  the  following  test 
(CHARLES  RICK  3) :  Ten  grains  of  the  powdered  chlorate,  in  a 
five-inch  test-tube,  are  covered  with  strong  hydrochloric  acid  to 
the  depth  of  about  one  inch,  the  evolution  of  gas  is  allowed  to 
continue  about  one  minute,  when  1^  volumes  of  water  are  added, 
and  the  gas  is  removed  from  the  upper  part  of  the  test-tube  by 
blowing  it  out  with  a  small  bent  glass  tube.  Pour  in  water  of 
ammonia,  without  shaking,  to  form  a  layer  about  half  an  inch 
deep,  and  remove  the  cloud  of  ammonium  chloride  by  blowing 
it  out  as  before.  Now  add  a  few  drops  of  the  liquid  to  be  test- 
ed, letting  it  flow  down  the  side  of  the  test-tube.  If  phenol  be 
present  a  colored  layer  or  "ring"  will  appear,  rose-red  to  red- 
brown.  Creosote  gives  the  same  reaction. 


1  An  adaptation  of  Froehde's  reagent.  DAVY:  Phar.  Jour.  Trans.  [3] 
8,  1021;  Jour.  Chem.  Soe.,  34,  809.  The  reagent  for  alkaloids  :  FROEHDE, 
1866:  ArcMv.  d.  Phar.,  126,  54;  Zeitsch.  anal.  Chem.,  5,  214;  Pro.  Am.  Phar. 
Asso.,  15,  241.  DRAGETSDORFF,  1872:  "Gericht.  Chem.  organ.  Gifte."  This 
work,  p.  51. 

2 1876:  Liebig's  Annalen,  181,  53;  180,  248;  182,  160;  Jour.  Chem.  Soc., 
30,  313,  639;  note  by  WRIGHT,  314. 

3 1873:  Am.  Jour.  Phar.,  45,  98. 


CARBOLIC  ACID.  401 

Other  tests  are  obtained  by  action  of  Ammonia  and  Chlorine, 
Ammonia  and  Hypochlorite,  and  by  Millon's  reagent.1 

Pure  phenol  does  not  reduce  Fehling's  solution,  and  but 
slowly  reduces  silver  and  mercury  salts,  but  reduces  permanga- 
nate, both  in  acid  and  in  alkaline  solutions.  With  concentrated 
sulphuric  acid,  phenolsulphonic  acid,  C6H6SO4,  is  slowly  form- 
ed, almost  without  color  when  the  phenol  is  pure.  The  phenol- 
sulphonates  of  alkali  metals  are  soluble  in  alcohol,  and  those  of 
other  metals,  including  barium  and  lead,  are  soluble  in  water, 
these  solubilities  giving  separations  from  sulphuric  acid.  On 
distilling  phenolsulphonic  acid,  phenol  is  obtained.  See  Sulpho- 
carbolic  Acid. 

kk  Carbolic  acid  coagulates  albumen  or  collodion  (difference 
from  creosote).  .  .  .  One  volume  of  liquefied  carbolic  acid,  con- 
taining five  per  cent,  of  water,  forms,  with  one  volume  of  glyce- 
rin a  clear  mixture  which  is  not  rendered  turbid  by  the  addi- 
tion of  three  volumes  of  water  (absence  of  creosote  and  cresylic 
acid)."— U.  S.  Ph.,  1880. 

e. — Separations. — Carbolic  acid  can  be  obtained  &y  distilla- 
tion from  acid  or  neutral  liquids  without  loss.  Less  volatile  than 
water,  the  phenols  are  yet  carried  over,  slowly,  with  vapor  of 
water,  and  the  operation  requires  conditions  similar  to  those 
needful  for  distillation  of  the  essential  oils.  In  alkaline  aqueous 
solutions  the  phenols  are  held  nearly  or  quite  secure  from  vapori- 
zation, so  that  these  solutions  can  be  concentrated  on  the  water- 
bath  without  loss  of  phenol,  though  as  to  the  limits  of  the  reten- 
tion of  phenol  by  hot  alkalies  when  very  dilute  further  proof  is 
desirable.  Potassium  hydrate  is  the  best  alkali.  Alcohol  and 
other  more  volatile  neutral  bodies  are  easily  removed  by  evapora- 
tion or  distillation  from  alkaline  mixtures  of  carbolic  acid.  Be- 
fore distilling  phenol,  therefore,  alkaline  liquids  and  mixtures 
— such  as  "  carbolate  of  lime  "  and  "  soda-phenol " — should  be 
acidified  by  adding  an  acid,  in  most  cases  sulphuric  acid,  some- 
times hydrochloric  or  phosphoric  acid.  But  phenol  may  be  dis- 
tilled, with  water,  from  a  neutral  mixture.  Dry  distillation, 

1  Detailed  reports  upon  qualitative  tests  for  phenol  have  been  given  as  fol- 
lows: WALLER,  1881:  School  of  Mines  Quarterly ,  1881,  Jan.;  Chem.  News,  43, 
151.  ALMEN,  1877:  Archiv.  d.  Phar.  [3]  10,  44;  Jour.  Chem  8oc.,  32,  360. 
ALLEN,  1878:  Analyst,  3,  319;  Jour.  Chem.  /SV?c.,36,  182.  HIRSCHSOHN,  Phenol 
and  Thymol,  Dorpat,  1881:  Phar.  Jour.  Trans.  [3]  12,  21;  Am.  Jotir.  Phar., 
53,  459;  Jour.  Chem.  Soc.,  40,  942.  Regarding  Detection  and  Estimation  in 
the  Urine — BAUMANN,  1882:  Zeitsch.  phyaiolog.  Chum.,  6,  183;  Jour.  Chem. 
Soc.,  42,  106.  BNGEL,  1881:  Ann.  Chim.  Phys.  [5]  20,  230;  Jour.  Chem. 
Soc.,  40,  114. 


402  PHENOL. 

without  addition,  in  glass  vessels  over  the  flame,  is  directed  by 
ALLEN  for  recovering  from  the  siliceous  material  of  "  carbolic 
acid  powders." 

In  analysis  of  animal  tissues,  or  indeterminate  organic  mix- 
tures, in  cases  of  poisoning,  the  finely  cut  material  is  digested, 
after  slight  acidulation  with  sulphuric  acid,  to  obtain  an  aqueous 
solution  of  all  the  phenol.  If  concentration  of  the  extract  is 
undertaken  before  distilling,  the  analyst  must  choose  a  method 
suited  to  the  material  and  conditions.  Extraction  with  ether  has 
been  recommended  in  this  case,  and  it  may  serve  if  there  is  little 
fat.  The  ether  solution  may  be  shaken  with  very  slightly  alka- 
line water,  the  ether-layer  and  dissolved  ether  evaporated  off, 
and  the  aqueous  solution  acidified  and  distilled.  In  any  case  the 
last  distillate  is  divided  into  aliquot  parts  by  volume,  for  quali- 
tative and  quantitative  determinations,  the  bromine  reaction 
being  most  serviceable.1  Phenol  is  eliminated  freely  by  the  kid- 
neys. 

In  the  Urine  phenol  appears  in  salts  of  phenylsulphuric  acid, 
chiefly  KC6H5SO4,  formed  by  union  of  the  excretory  phenol 
with  the  sulphates  of  the  urine.  Therefore  it  is  a  clinical  result 
that  the  sulphates  of  the  urine,  as  noted  by  the  precipitation  of 
barium,  diminish  in  measured  proportion  to  the  increase  of  ex- 
cretory phenol.  The  later  investigations  *  carefully  distinguish 
the  urinary  form  of  phenol,  above  named,  from  its  isomer,  phe- 
nolsulphonic  acid  (see  Sulphocarbolates).  When  much  phenol 
is  excreted,  and  in  cases  of  phenol  poisoning,  the  urine  some- 
times, but  not  invariably,  has  a  greenish- brown  color.  Baumann 
separates  the  sulphates  from  the  phenylsulphates  and  determines 
the  sulphuric  acid  of  the  latter  and  of  other  ethersulphuric 
acids  as  follows :  25  to  50  c.c.  of  the  urine  is  acidified  with  ace- 
tic acid,  diluted  with  an  equal  volume  of  water,  treated  with  an 
excess  of  barium  chloride  solution,  and  warmed  three-quarters  of 
an  hour  on  the  water-bath,  for  the  full  precipitation  of  all  the 
simple  sulphates.  .The  filtrate  is  boiled  with  hydrochloric  acid 
to  decompose  the  conjugated  acids  and  throw  down  their  sul- 
phuric acid  as  barium  sulphate,  which  is  then  washed  with  hot 

1  For  the  Toxicology  of  Carbolic  Acid,  including  analysis,  see  Wharton  and 
Stille,  "  Med.  Juris.,"  4th  ed.  1884,  vol.  2,  p  96.    Blyth's  "Poisons,"  London, 
1884.     ENGEL,  1881:  Ann.  Ghim.  Phys.  [5]  20,  230;  Jour.  Chem.  Soc.,  40,  114. 
BISCHOFF,  On  distribution  in  the  body,  1883:  Ber.  d.  chem.  (res.,  16,  1337;  Jour. 
Chem.  Soc.,  44,  1020.  » 

2  BAUMANN,  supported  by  CLOETTA  and  SCHAER. 


CARBOLIC  ACID.  403 

alcohol  to  remove  resins,  etc.,  and  prepared  for  weighing. 
The  phenylsulphates  are  more  easily  decomposed  by  mineral 
acids  and  heat  than  the  phenolsulphonates.  From  the  weight 
of  barium  sulphate  obtained  by  decomposition  of  the  phenyl- 
sulphates the  quantity  of  excretory  phenol  is  calculated : 

EaSO4  :  C6H6O::232.8  :  94.0::1  :  0.40378. 

The  phenol  of  the  urine  may  also  be  estimated  by  distilling  at 
length,  adding  hydrochloric  acid  to  liberate  phenol  from  the 
phenylsulphates,  and  determining  the  phenol,  in  the  distillate, 
by  the  volumetric  method  with  bromine. 

In  separation  by  solvents,  ether,  hot  water,  and  alkaline 
water  are  most  serviceable,  but  carbon  disulphide,  benzene,  and 
chloroform  may  be  employed.  Petroleum  benzin  takes  up  but 
traces.  Ether  extracts  the  phenols  from  aqueous  solutions  not 
alkaline,  and  from  other  materials  not  acted  on  by  the  ether. 
It  is  to  be  applied  in  repeated  portions  till  no  more  phenol  is 
obtained.  Liquids  are  to  be  shaken  with  the  ether  in  a  test- 
glass  or  stoppered  cylinder,  when  the  ether-layer  is  allowed  to  rise 
and  is  taken  off.  This  is  well  done,  exactly  as  water  is  ex- 
pelled from  an  ordinary  wash-bottle,  the  delivery  tube  (not  too 
large)  playing  up  and  down  in  the  stopper  to  take  up  the  ether 
(p.  36).  Or,  with  use  of  a  separator,  the  watery  layer  may  be 
drawn  away.  The  ether  may  be  removed  by  spontaneous  evapo- 
ration, or  in  a  current  of  warm  air  driven  by  a  bellows  or  drawn 
by  a  filter- pump,  with  very  little  loss  of  the  phenol.  But  to 
prevent  this  loss  it  is  well,  if  the  operation  permits,  to  add 
enough  water,  made  slightly  alkaline  with  potassium  hydrate,  to 
take  up  the  phenol  from  the  ether-solution.  Hot  water  extracts 
carbolic  acid  from  fats,  a  very  thorough  application  being  need- 
ful. From  animal  tissues  acidulated  hot  water  has  been  mostly 
used,  sulphuric  acid  acidulation  being  preferred.  JACOBSEN 
(1885)  extracted  with  benzene  or.  ether.1  Materials  not  at  all  act- 
ed on  by  alkalies  may  be  most  efficiently  exhausted  of  phenol  by 
water  alkaline  with  about  nine  per  cent,  of  potassium  hydrate. 
The  water  solutions,  neutral  or  acid,  if  pure  enough  to  require 
no  further  separation,  are  ready  for  precipitation  of  phenols  by 
bromine,  as  directed  for  the  Quantitative  work. 

In  the  valuation  of  Crude  Carbolic  Acid  the  per  cent,  of 
tar-oils  is  briefly  found  (ALLEN)  by  shaking,  in  a  graduated  tube 


1  W.  JACOBSEN,  1885:  Dorpat  Dissertation :  Zeitsch.  anal.  CJiem.,  25,  607. 


404  PHENOL. 

or  jar,  with  a  nine  per  cent,  caustic  soda  solution,  and  reading 
off'the  resulting  layers  of  undissolved  liquid  (substances  besides 
phenols  and  water).  But  some  naphthalene  and  other  non-phe- 
nol bodies  are  dissolved  by  the  alkali,  which  therefore  must  be 
as  dilute  as  will  barely  dissolve  the  phenols.  An  equal  volume 
of  petroleum  benzin  previously  added,  and  accounted  for,  dimin- 
ishes the  solution  of  "  tar-oils  "  by  the  alkali.  An  assay  5y  dis- 
tillation of  the  crude  carbolic  acid  is  used  at  works  (CHARLES 
LOWE  '),  the  phenol  distillates  being  compared  in  solidifying 
points  with  known  mixtures  of  good  carbolic  and  cresylic  'acids. 

Phenols  may  be  separated  or  estimated  in  special  cases  by 
conversion  into  phenolsulphonic  acid.  The  latter  may  be  ob- 
tained in  its  soluble  barium  salt,  and  the  barium  precipitated  as 
a  sulphate,  one  molecule  of  barium  sulphate  denoting  one  mole- 
cule of  the  phenol,  the  same  as  from  the  phenylsulphate  above 
given.  The  formation  and  characteristics  of  the  phenolsulpho- 
nates  are  to  be  observed,  as  given  under  Sulphocarbolates. 

f. — Quantitative. — For  chemical  estimation  the  precipitation 
with  bromine  appears  to  be  best  suited.  The  precipitate  was 
stated  by  LANDOLT*  to  be  C0H3Br3O=z  330.4;  and  when  it  was 
washed  with  water,  and  dried  in  a  desiccator,  this  author  ob- 
tained fair  gravimetric  results.  The  precipitate,  however,  is  not 
easily  washed,  and  it  both  melts  and  vaporizes  on  the  water  bath. 
The  volumetric  method  is  more  satisfactory.  WALLER  3  em- 
ploys an  aqueous  solution  of  bromine  by  which  the  solution  es- 
timated is  exactly  compared  with  a  solution  of  phenol  of 
known  strength.  KOPPESCHAAR  uses  a  standardized  solution  of 
5KBr -|- KBrO3 ,  added  in  excess,  then  acidulates,  and  titrates 
back  with  thiosulphate  solution  (also  used  to  standardize  the 
bromide),  with  use  of  iodide  as  an  indicator.4  SEUBERT,&  estimat- 
ing phenol  in  Surgical  Dressings,  found  it  necessary  to  filter 
before  adding  the  iodide,  as  tribromophenol  liberates  iodine  from 
iodide.  WEINREB  and  BONDI  6  report  that  the  precipitate  is  not 
C6H3Br3O,  but  CeH2Br4O  or  (C6H2Br3OBr),  and  that  Koppe- 
schaar's  correct  results  were  indebted  to  the  reaction  with  the 
iodide  of  potassium  used  as  an  indicator  (in  presence  of  the  pre- 

1  Allen's  "  Commercial  Organic  Analysis,"  1879,  i.  311. 

*  Ber.  d.  chem.  Oes.,  4,  770;  Chem.  News,  44,  217.  See  WEINREB  and 
BONDI,  below. 

3 1881 :  Chem.  News,  43,  157. 

4 1876:  Zeitsch.  anal.  Chem.,  15,  233;  Jour.  Chem.  Soc.,  31,  746.  DEGE. 
NER,  1878:  Jour.  pr.  Chem.  [2]  17,  390;  Jour.  Chem.  Soc.,  34,  918. 

5 1882:  Arch.  Phar.  [3]  18,  321;  Jour.  Chem.  Soc,,  42,  106. 

6 1885:  Monat.  f.  Chem.  (1885),  6,  506;  The  Analyst,  n,  39. 


SULPHOCARBOLA  TES.  405 

eipitate),  whereby  C6H3Br3O  is  at  last  formed,  when  (as  Seubert 
states)  iodine  is  liberated.  CHANDELON  1  uses  bromine  dissolved 
in  dilute  alkali  solution,  as  hypobromite,  the  estimation  being 
applied  to  the  Urine,  as  well  as  to  surgical  dressings.  As  to 
estimations  in  the  urine  and  in  dressings,  the  method  of  BAU- 
MANN  has  been  given  under  p.  402.  The  directions  given  by 
Dr.  Waller,  in  the  method  first  above  named,  are  as  follows  : 

Solutions  required  :  (1)  Ten  grams  pure  crystallized  phenol 
[of  the  dryness  desired  as  a  standard]  in  water  to  make  1  liter,  a 
solution  not  suffering  alteration  for  some  months.  (2)  A  solu- 
tion of  bromine  in  water.  (3)  Diluted  sulphuric  acid,  of  15  to 
20  per  cent,  strength,  saturated  with  alurn.  This  is  needed  to 
enable  the  precipitate  to  settle.  Of  the  sample  10  grams  are  in- 
troduced into  a  liter-flask,  water  is  added,  with  agitation,  to  make 
one  liter,  the  solution  mixed  and  some  of  it  filtered  (through  a 
dry  filter).  Of  the  clear  filtrate  10  c.c.  are  run  into  a  six  or 
eight  ounce  glass-stoppered  bottle,  and  about  30  c.c.  of  the  alum 
solution  are  added.  In  anotlier  bottle  of  the  same  kind  5  c.c. 
or  10  c.c.  of  the  standard  phenol  solution  are  taken,  again  with 
about  30  c.c.  of  the  alum  solution.  Bromine  solution  is  now 
added,  from  the  burette,  to  the  bottle  containing  standard  phenol 
solution,  till  no  more  precipitate  forms,  the  bottle  being  stop- 
pered and  shaken  after  each  addition,  for  the  separation  of  the 
precipitate,  and  the  end-reaction  being  further  indicated  by  ap- 
pearance of  a  yellow  color  in  the  clear  solution  when  a  very 
slight  excess  of  the  bromine  is  reached.  Near  the  end  the  pre- 
cipitate forms  slowly.  The  solution  from  the  sample  is  titrated 
in  the  same  way,  Then,  c.c.  of  bromine- water  required  for 
10  c.c.  standard  phenol  sol.  :  c.c.  bromine- water  required  for 
10  c.c.  ,from  sample  ::  100  :  x  —  percentage  of  the  standard 
phenol  in  the  sample. 

g. — Impurities  in  Carbolic  Acid. — Alkaline  dilutions  are  re- 
vealed by  their  alkaline  reaction,  and  by  giving  a  precipitate 
when  neutralized  by  adding  dilute  sulphuric  acid.  If  an  article 
presented  as  liquid  carbolic  acid,  pure  or  impure,  is  freely  misci- 
ble  with  water,  it  may  be  either  the  very  dilute  carbolic  acid 
water  or  an  alkaline  mixture.  Regarding  the  Tar  Oils  see 
p.  404.  Concerning  the  quality  of  "  Carbolic  Acid  of  America," 
E.  M.  HATTON,  1886 :  Proc.  Am.  Pharm.,  34,  70. 

SULPHOCARBOLATES. — Salts   of   phenolsulphonic  acid,  C6H4. 

>1882:  Bull.  Sue.  Chim.  [2]  38,  69;  Jour.  Cham.  Soc.,  44,  Abstracts,  124. 
Further,  CLOETTA  and  SCHAER,  1881-82:  Jour.  Cheni.  Soc.,  42,  106. 


4o6  PHENOL. 

OH  .  SO3H  (C6H6SO4  =  174,  monobasic).  Phenolsulphonates. 
Sulphophenates.  Phenolsulfosauresalz. — There  are  two  phenol- 
sulplionic  acids  easy  of  production  and  liable  to  occur  in  sulpho- 
carbolates  of  commerce — namely :  (1)  Phenol  orthosulphonic 
acid,  having  OH  :  SO3H  =  1:2,  produced  by  continued  con- 
tact of  phenol  and  concentrated  sulphuric  acid  in  equal 
parts  at  ordinary  temperatures,  and  the  proper  constituent  of 
medicinal  sulphocarbolates.  (2)  Phenol  para-sulphonic  acid, 
OH  :  SO3H  =±=  1  :  4,  produced  by  heating  the  ortho  acid.  Phenol 
disulphonic  acid,  CLH3 .  OH .  (SO3H)2 ,  is  formed  by  heating  phe- 
nol with  excess  of  sulphuric  acid.1  Cresolsulphonic  acid  and 
xylolsulphonic  acid  are  formed  when  crude  carbolic  acid  or 
other  mixtures  of  cresol  and  xylol  are  digested  with  concentrated 
sulphuric  acid. 

In  preparing  phenolorthosulphonic  acid  equal  parts  of  phenol 
and  concentrated  sulphuric  acid  are  mixed,  after  twenty-four 
hours  water  is  added,  and,  in  some  way,  the  (unavoidable)  free 
sulphuric  acid  is  removed.  This  may  be  done  by  saturating 
both  the  phenolsulphuric  and  sulphuric  acids  with  barium  car- 
bonate and  filtering;  or  by  carefully  saturating  only  the  sulphuric 
acid,  so  that  the  filtrate  shall  precipitate  neither  a  barium  salt 
nor  a  sulphate ;  or  by  saturating  both  acids  with  sodium  carbon- 
ate, evaporating,  dissolving  the  phenolsulphate  in  alcohol,  and 
crystallizing  from  the  filtrate.  The  higher  the  temperature  of 
action  of  the  sulphuric  acid,  and  the  greater  the  excess  of  this 
acid,  the  more  of  phenolparasulphonic  acid  will  result,  and  its 
production  is  not  wholly  avoided  in  any  case. 

The  potassium  phenolorthosulphonate  melts  at  240°  C.,  and 
crystallizes  in  needles  with  two  molecules  of  water ;  the  potas- 
sium phenol parasulphonate  melts  above  260°  C.  and  crystallizes, 
anhydrous,  in  hexagonal  plates.2  Phenolsulphonates  are  decom- 
posed with  reproduction  of  sulphuric  acid,  by  boiling  with  nitric 
acid  or  with  hydrochloric  acid,  and  slowly  by  boiling  with  water. 
The  nitric  acid  reacts  vigorously,  as  with  phenol,  forming  nitro- 
phenic  acids.  Even  in  water  solution  at  ordinary  temperatures 
free  phenolsulphonic  acid  suffers  gradual  decomposition. 

The  metallic  sulphocarbolates  are  all  measurably  soluble  in 
water,  the  barium  and  lead  salts  included  (separation  from  sul- 
phates). The  sodium  salt  is  NaC6H5SO4. 2H2O.  The  alkali 

'Sulphuric  acid,  HO(S03H)'  or  HO(SO2)''OH 
Phenolsulphonic  acid,  HO.C6H4.S03H  [C6H6S04] 
Phenoldisulphonic  acid,  HO.C6H3.(SO3H)2 
Phenylsulphuric  acid,  C6B5O.S03e  [C6H6S04] 

'"Watts's  Dictionary,"  viii.  1538. 


PL  A  NT  ANAL  YS/S.  407 

sulphocarbolates  are  soluble  in  much  alcohol  (another  separation 
from  sulphates).  Further,  the  sulphocarbolates  are  identified  by 
giving  the  chief  reactions  of  phenol — those  with  nitric  acid, 
bromine,  and  ferric  chloride — and  by  giving  the  reactions  of 
sulphates  only  after  decomposing  with  boiling  nitric  or  hydro- 
chloric acid. 

PHYSETOLEIC  ACID.  See  FATS  AND  OILS,  pp.  246, 250. 
PICRACONITINE.  See  ACONITE  ALKALOIDS,  pp.  18,  20. 
PIT  URINE.  See  MIDKIATIC  ALKALOIDS,  p.  341. 

PLANT  ANALYSIS. — The  chemical  analysis  of  vegeta- 
ble tissues.  Phytochemical  analysis. 

Systematic  methods  of  chemical  analysis  of  plants  have  been 
presented  as  follows : 

FREDERICK  ROCHLEDER,  M.D.,  professor  of  organic  chemistry  in  the  Uni- 
versity of  Prague,  1858:  Wiirzburg,  Germany.  English  translation  by  Wil- 
liam Bastick,' London,  1860:  Phar.  Jour.  Trans.  [2]  i,562.  Same  translation 
revised  by  Professor  John  M.  Maisch,  Philadelphia,  1860:  Am.  Jour.  Phar., 
33,  81,  et  seg. ;  reprinted  in  80  pages,  1862. 

Dr.  G.  C.  WITTSTEIN,  Miinchen,  1868:  "  Anleitung  zur  chemischen  Analyse 
von  Pflanzentheilen  auf  ihre  organischen  Bestandtheilen,"  355  pp.,  Nordlingen. 
An  English  translation,  "The  Organic  Constituents  of  Plants  and  their  Chemi- 
cal Analyses,"  by  F.  von  Mueller,  Ph.D.,  F.R.S.,  Melbourne,  1878,  pp.  332. 
The  "  plant  analysis  "  is  included  in  Part  II.,  49  pages. 

HENRY  B.  PARSONS,  Ph.C.,  assistant  chemist  in  the  Department  of  Agricul- 
ture, Washington,  1880:  "  A  Method  for  the  Proximate  Chemical  Analysis  of 
Plants,"  American  Chemical  Journal,  I,  377-391;  Am.  Jour.  Phar.,  52,  210; 
Phar.  J'>ur.  Trans.  [3]  10,  793;  Jour.  Chem.  Soc.  (abstract),  38,  754;  Her.  d. 
chem.  Ges.,  13,  1370;  Chem.  Newx  (in  full),  41,  256,  267:  Year-book  of  Phar., 
London,  1880,  5u:  Jahres.  d.  Pharm.,  1880,  99;  Allen's  "  Commercial  Organic 
Analysis,"  London,  second  edition,  1885,  i.  356  (tabulated  abstract);  Lyons's 
"Pharmaceutical  Assaying,"  Detroit,  1886,  p.  37  (tabulated  abstract). — Given 
•in  full  in  th"  following  page*. 

GEORG  DRAGENDORFF,  professor  of  pharmacy  in  the  University  of  Dorpat, 
Russia,  1882:  "Die  qualitative  und  quantitative  Analyse  von  Pflanzen  und 
Pflanzentheilen,'  285  pp.,  Gottingen.  An  English  translation  by  Henry  G. 
Greenish,  London,  1884:  "  Plant  Analysis:  Qualitative  and  Quantitative,"  280 
pp.  A  French  translation  in  Fremy's  "  Encyclopedie  Chimique,"  Paris,  1885, 
tome  viii.  (from  the  author,  without  credit  to  previous  publication).  An  out- 
line of  Dragendorff's  scheme  is  given  in  the  following  pages. 

Good  examples  of  plant  analysis,  chiefly  according  to  DragendorfFs  scheme, 
have  been  presented  by  Helen  C.  DeS.  Abbott,  Philadelphia.  In  1884,  analysis 
of  "Fouquiera  splendens,"  Proc.  Am.  Assoc.  Adv.  Sci.,  33,  190;  Am.  Jour. 
Phar.,  57,  81.  In  1885,  analysis  of  "Yucca  angustifolia,"  Proc.  Am.  Assoc. 
Adv.  Sci.,  34,  125  (abstract). 

Other  examples  are  found  in  reports  of  results  by  Parsons's  scheme  as  fol- 
lows: John  Hoehn,  Ann  A'/bor,  1882,  analysis  of  "cheken  leaves,"  Contribu- 
tions Chem.  Lab.  Univ.  Mich.,  I,  39  (abstract).  William  Heim,  Ann  Arbor, 
analysis  of  '•  Piscidia  erythrina,"  ibid.,  i,  38  (abstract);  Ther.  Gazette,  1882,  p. 


4o8  PLANT  ANALYSIS. 

254.    Henry  Palmer,  Ann  Arbor,  analysis  of  "  Viburnum  lentago,"  Proc.  Mich. 
State  Phar.  Awe.,  3  (1885),  158. 

Results  of  plant  analyses  by  Mr.  Parsons  himself  are  extant  as  follows: 
Analysis  of  "damiana"  (Turnera  aphrodisiaca),  1880:  New  Remedies,  9,  261; 
Phar.  Jour.  Trans.  [3]  II,  271.  Of  "Eupatorium  perfoliatum,"  1879:  Am. 


Jour.  Phar.,  51,  342;  Archiv  der  Phar.  [3]   15,  557.     Of  "Berberis   aquii'o- 

[,83;   • 

is.,  15,  2745.     Of  "Usti 
New  Remedies,  n,  80;  Phar.  Jour.  Trans.  [3]  12,  810.      Plant  analyses  in  the 


lium   (var.  repens),"  1880r   New  Remedies,  n,  83;  Phar.  Jour.  Trans.  [3]  13, 
46;  Ber.  d.  chem.  Oes.,  15,  2745.     Of  "Ustilago  maidis  (corn  smut),"  1880: 


Reports  of  the  Department  of  Agriculture  at  Washington,  for  1880,  1881,  1882, 
as  accredited  to  Mr.  Parsons  by  the  chemist,  Dr.  Collier.  See  also  an  excellent 
article  by  Mr.  Parsons  on  "Some  Constituents  of  Plants,"  1879:  New  Reme- 
dies, 8,  168. 

PAKSONS'S  METHOD  FOR  THE  CHEMICAL  ANALYSIS  OF  PLANTS/ 

Prefatory. — It  must  be  premised  that  no  one  method  is  applicable  in  all 
cases,  and  that  the  operator  will  so  modify  and  adapt  the  proposed  processes- 
as  to  best  attain  the  truths  he  seeks.  If  the  present  scheme  shall  serve  merely 
as  an  example,  to  be  improved  upon  as  discoveries  multiply,  it  will  at  least 
have  served  to  stimulate  to  the  more  thorough  study  of  a  much-neglected  yet 
very  important  branch  of  analysis.  The  student,  when  first  entering  upon  the 
study  of  plant  analysis,  is  perplexed  and  disheartened,  owing  to  the  lack  of 
any  elementary  treatise  in  which  he  may  find  directions  for  the  quantitative 
estimation  of  the  various  plant  constituents.  The  works  of  Rochleder  and 
Wittstein,  while  giving  most  valuable  assistance  in  the  investigation  of  special 
constituents  and  their  separation  from  large  quantities  of  the  crude  herb,  still 
fail  to  give  clear  and  practicable  directions  for  the  quantitative  estimation  of 
each  constituent.  Von  Mueller's  latest  enlarged  edition  of  Wittstcin's  "  Plant 
Analysis  "  gives  a  scheme,  most  excellent  in  many  respects,  yet  cumbered  with 
tiresome  methods  of  extraction  and  manipulation,  which  serve  to  unnecessarily 
lengthen  the  time  required  for  making  the  analyses,  without  increasing  the 
accuracy  of  results  obtained. 

Too  many  American  analyses  of  plants  have  been  summarized  thus:  ''The 
plant  contains  gum,  resin,  tannin,  a  volatile  oil,  and  a  peculiar  bitter  principle, 
to  which  may  be  ascribed  its  medicinal  activity."  The  foreign  journals  bring 
occasionally  most  excellent  examples  of  accurate  examinations  of  vegetable  sub- 
stances; as  instances  may  be  cited  the  examination  of  ginger,  by  J.  C.  THRESH,** 
and  of  ergot,3  aloes,4  and  other  articles  by  Prof.  DRAGENDORFF.  To  these 
sources  the  student  must  look  for  his  best  models  (p.  407  and  above). 

1  The  publications  of  this  method  are  cited  above,  p.  407.  Mr.  Parsons 
disclaimed  any  aim  to  originality,  in  the  resources  used  in  the  scheme  (presented 
at  request  of  the  author  of  this  work),  but  submitted  the  plan  as  an  outgrowth 
of  his  own  experience,  in  a  varied  practice  of  chemical  analysis  of  plants  and 
vegetable  tissues. 

8  Phar.  Jour.  Trans.  [3]  10,  81,  Aug.,  1879;  Am.  Jour.  Phar.,  1879,  51, 
519. 

*Phar.  Jour.  Trans.  [3]  6,  1001,  June  17,  1876;  Am.  Jour.  Phar  ,  1876, 
p.  413;  1878,  p.  335. 

4  "  Werthbestimmung,"  1874,  p.  110. 


PARSONS' S  METHOD.  409 

In  following  the  plan  now  presented,  the  use  of  the  apparatus  for  con- 
tinuous percolation  is  strongly  urged  for  the  extractions  with  benzene,  alcohol, 
and  other  volatile  solvents.  A  very  simple  and  inexpensive  "extraction  appa- 
ratus "  has  been  described  by  various  American  and  foreign  chemists.1 

"In  any  convenient  water-tight  vessel  is  a  worm  of  block-tin  pipe,  having 
an  internal  diameter  of  9  mm.  and  a  length  of  about  2.5  meters.  The  lower 
(external)  part  of  this  worm  is  fitted  by  an  ether-soaked  velvet  cork  to  a  glass 
percolator  having  a  diameter  of  4  cm.,  a  length  of  20  cm.  to  the  constriction, 
and  5  cm.  below.  Within  this  percolator  is  a  smaller  tube,  flanged  at  the  top 
and  bottom,  and  suspended  by  fine  platinum  or  copper  wires.  This  tube  has 
a  diameter. of  2.5  to  2.8  cm.  and  a  length  of  14  cm. ;  the  bottom  is  covered  by 
filter-paper  and  fine  washed  linen,2  tied  on  by  linen  thread.  The  weighed  sam- 
ple of  the  finely  powdered  herb  is  placed  within  this  tube  for  extraction.  A 
light  glass  flask,  weighing  about  30  grams,  is  fitted  by  an  ether-soaked  cork  to 
the  outer  percolator."  Having  introduced  the  solvent  into  this  glass  flask,  the 
connections  are  made  secure,  and  heat  is  applied  by  a  water-bath  to  the  flask. 
If  the  liquid  is  too  slowly  volatilized  the  addition  of  a  little  common  salt  to  the 
water  in  the  bath  serves  to  remove  the  trouble. 

Next  in  importance  is  the  use  of  a  good  tared  filter.  The  form  originally 
presented  by  P.  A.  GOOCH  3  leaves  little  to  be  desired.  It  may  be  made  by  per- 
forating with  fine  holes  the  bottom  of  air  ordinary  platinum  crucible,  and  fit- 
ting it  accurately  to  a  perforation  made  in  a  large  rubber  cork ;  this  cork  con- 
nects it  with  a  receiving  vessel,  which  in  turn  is  connected  with  a  Bunsen's 
pump.  Fine  asbestos  suspended  in  water  is  poured  into  the  crucible,  the  air 
exhausted  from  the  receiving  vessel,  and  thus  a  firm,  thin  layer  of  asbestos  is 
deposited  on  the  bottom  of  the  crucible.  After  ignition  and  weighing,  the  cru- 
cible is  ready  for  the  reception  of  any  precipitate  which  it  is  desired  to  separate 
and  weigh. 

The  use  of  these  two  pieces  of  apparatus  will  eliminate  two  grave  sources 
of  error,  viz.,  incomplete  extraction  of  soluble  matters,  and  inaccuracies  intro- 
duced by  the  use  of  tared  paper  filters. 

The  other  necessary  apparatus  is  simple,  and  includes  one  or  more  plati- 
num crucibles  and  evaporating  dishes,  accurate  burettes  and  graduated  cylin- 

'B  TOLLENS:  Zeitsch.  anal.  Chem..,  17,  320  (1878):  New  Remedies,  7, 
335,  Nov.,  1878.  W.  0.  ATTWATER:  Proc.  Am.  (  hem.  Soc.,  2,  85  (illustrat- 
ed). S.  W.  JOHNSON:  Am.  Jour.  Sci.,  13,  196.  H.  B.  PARSONS:  New 
Remedies,  8,  293  (illustrated),  Oct.,  1879.  F.  SOXHLET,  1879:  Ding,  polyt. 
Jour.,  232,  461;  Zeitsrh.  anal.  Chem.,  ig,  365.  MEDICUS,  1880:  Zeitsch.  anal. 
Chem.,  19,  163;  New  Remedies,  9,  167  (illustrated). 

2  In  place  of  the  linen  and  filter-paper  may  be  substituted  fine  brass  or  plati- 
num wire  gauze.  Asbestos  suspended  in  water  may  then  be  poured  in  to  form 
a  fine  felt.  The  tube  can  then  be  dried  and  weighed,  and  the  amounts  ex- 
tracted may  be  found  by  the  loss  of  weight  of  the  tube  and  substance.  A  little 
experimentation  will  show  the  operator  how  to  prepare  and  use  the  tube.  It 
is  but  an  adaptation  of  the  Gooch's  Filter  here  recommended. 

sProc.  Am.  Acad.  Sci.,  13,342  (1878);  New  Remedies,  7,  200  (Oct., 
1878);  Am.  Chem.  Jour.,  i,  317  (illustrated). 


410  PLANT  ANALYSIS. 

tiers,  a  good  balance  sensitive  to  at  most  0.0005  gram,  and  the  ordinary  glass 
and  porcelain-ware  found  in  all  laboratories. 

It  is  assumed  that  whoever  attempts  the  analysis  of  a  plant  is  informed  as 
to  the  normal  constituents  to  be  sought,  and  that  he  has  had  considerable  expe- 
rience in  inorganic  analysis  and  in  the  identification  of  the  principal  classes  of 
proximate  constituents  which  he  now  undertakes  to  estimate  quantitatively. 
Accordingly,  tests  for  identification  will  not  be  here  presented ;  they  should, 
however,  never  be  omitted.  The  necessity  of  recording  in  detail  all  physical 
and  chemical  peculiarities  with  every  weight  that  is  taken  is  self-evident. 

I.  Preparation  of  Sample. 

The  air-dry  specimen  should  be  carefully  examined,  and  all 
extraneous  substances  removed.  The  entire  sample  should  then 
be  ground,  or  beaten  in  an  iron  mortar,  until  it  will  all  pass 
through  a  sieve  having  from  40  to  60  meshes  to  the  linear  inch. 
After  thoroughly  mixing  this  sample,  take  of  it  about  100  grams, 
which  should  be  further  pulverized  until  it  will  all  pass  through 
a  sieve  having  from  80  to  100  meshes  to  the  linear  inch.  From 
this  smaller  portion  remove  all  iron,  derived  from  mill  or  mortar, 
by  use  of  a  magnet.  Then  place  in  a  clean,  dry  bottle,  which 
should  be  labelled  and  securely  corked.  This  small  sample  is  for 
the  analysis ;  the  larger  portion  should  be  reserved  for  the  sepa- 
ration of  those  proximate  principles  which  seem,  from  the  analy- 
sis, to  be  worthy  of  more  extended  investigation. 

II.  Estimation  of  Moisture. 

Dry  rapidly,  at  100°  to  1 20°  C.,  two  or  more  grams  of  the 
sample ;  the  loss  of  weight  equals  moisture  and  occasionally  a, 
little  volatile  oil.  In  some  cases  it  is  best  to  dry  at  a  lower  tem- 
perature, and  at  other  times  the  drying  should  be  conducted  in 
a  stream  of  hydrogen  or  carbonic  anhydride.1 

III.  Estimation  of  Ash. 

In  a  weighed  crucible  gently  ignite  two  or  more  grams  of 
the  sample  until  nearly  or  quite  free  from  carbonaceous  matter ; 
the  heat  should  not  be  permitted  to  rise  above  faint  redness,  or 
loss  of  alkaline  chlorides  may  occur.  Weigh  this  residue  as 
crude  ash,  and  in  it  determine : 

a. — Amount  Soluble  in  Water. — This  portion  may  contain 
chlorides,  sulphates,  phosphates,  and  carbonates  of  potassium  and 
sodium ;  also  slight  amounts  of  chlorides  and  sulphates  of  cal- 
cium and  magnesium. 

1  On  treatment  of  fresh  plants  for  drying,  and  on  methods  of  powdering, 
see  Dragendorff  s  "  Plant  Analysis,"  London  edition,  p.  6. 


PARSONS' S  METHOD.  411 

b.—  Insoluble  in  water;  Soluble  in  Dilute  Hydrochloric 
Acid. — The  residue  from  a  should  be  treated  with  a  slight  ex- 
cess of  hydrochloric  acid,  and  evaporated  in  a  porcelain  dish 
over  a  water- bath  until  all  free  acid  has  been  expelled ;  it  should 
then  be  again  moistened  with  hydrochloric  acid,  water  added, 
and  be  filtered  from  any  remaining  insoluble  substances.  This 
treatment  removes  carbonates  (with  decomposition)  and  phos- 
phates of  calcium  and  magnesium,  sulphate  of  calcium,  and  ox- 
ides of  iron  and  manganese. 

c, — Insoluble  in  Water  j  Insoluble  in  Dilute  Hydrochloric 
Acid  j  Soluble  in  concentrated  Sodium  Hydrate. — Boil  the  resi- 
due from  b  with  a  solution  containing  about  20  per  cent,  of 
sodium  hydrate.  This  treatment  removes  combined  silica  of  the 
ash.  The  residue  still  insoluble  is  sand  and  clay  which  adhered 
to  the  specimen  ;  this  residue  should  be  separated,  washed  tho- 
roughly, and  weighed. 

Always  determine  the  amounts  removed  by  the  above  treat- 
ment by  weighing  the  dried,  undissolved  residues.  The  ash,  as 
thus  estimated,  usually  includes  a  little  unconsumed  carbon,  to- 
gether with  more  or  less  carbonic  anhydride,  most  or  all  of 
which  was  not  originally  present  in  the  plant,  but  was  produced 
by  the  combustion  of  the  organic  matter.  For  most  purposes  it 
is  unnecessary  to  estimate  and  exclude  from  the  ash  this  carbonic 
anhydride ;  where  great  accuracy  is  desired,  a  complete  quantita- 
tive analysis  should  be  made,  the  amount  of  each  base  and  acid 
being  determined,  and  in  the  statement  of  results  only  those 
should  be  included  which  existed  originally  in  the  plant.  For 
this  purpose  it  is  necessary  to  burn  from  20  to  100  grams  of  the 
sample  ;  for  further  directions  consult  text  books  on  agricultural 
and  ino-ganic  analysis. 

IV.  Estimation  of  Total  Nitrogen. 

In  half  a  gram  or  more  of  the  sample  determine  total  nitro- 
gen by  combustion  [p.  230  or  229].  If  later  in  the  analysis  no 
other  nitrogenous  substances  are  discovered,  calculate  the  total 
amount  of  nitrogen  to  albuminoids  by  multiplying  by  6.25  [or 
6.33].  When  other  nitrogenous  compounds  are  present,  their 
content  of  nitrogen  should  be  determined  directly  or  by  diffe- 
rence ;  after  proper  deductions  have  been  made,  the  remaining 
nitrogen  should  be  calculated  to  albuminoids. 

V.  Estimation  of  Benzene  Extract. 

In  a  suitable  extraction  apparatus  completely  exhaust  5  grams 
of  the  sample  with  pure  coal-tar  benzene  (sp.  gr.  85-88,  boil- 


412  PLANT  ANAL  YSIS. 

ing  at  80°  to  85°  C.,  leaving  no  residue  when  evaporated).  The 
extraction  requires  from  four  to  six  hours'  continued  action  of 
the  solvent.  Carefully  evaporate  this  liquid  to  dryness  in  a 
weighed  dish,  and  record  its  weight  as  total  benzene  extract. 
This  extract  may  contain  volatile  oils  and  other  aromatic  com- 
pounds, resins,  camphors,  volatile  or  non-volatile  organic  acids, 
wax,  solid  fats,  fixed  oilfi,  chlorophyll,  other  colors,  volatile  or 
fixed  alkaloids,  glucosides,  almost  no  ash. 

To  the  weighed  extract  add  water,  again  evaporate  on  the 
water-bath,  and  complete  the  drying  in  an  air-bath  at  110°  C. 
In  absence  of  other  vaporizable  substances  the  loss  of  weight 
approximates  the  amount  of  volatile  oil.  If  the  presence  of  a 
volatile  alkaloid  is  suspected  (from  a  characteristic  odor  or  an 
alkaline  reaction),  add  a  drop  of  hydrochloric  acid  to  prevent  its 
volatilization.  Camphors  are  partially  dissipated  by  this  treat- 
ment ;  hence,  when  they  are  present,  this  evaporation  should  be 
dispensed  with. 

Treat  now  the  residue  with  a  moderate  amount  of  warm 
water,  allow  to  stand  until  cool,  then  filter  through  fine  paper 
by  aid  of  a  Bunsen's  pump.  In  half  of  the  aqueous  filtrate  de- 
termine total  organic  matter  and  ash ;  test  the  remaining  half 
for  alkaloids,  glucosides,  and  organic  acids  by  salts  of  lead,  sil- 
ver, barium,  and  calcium.  Care  must  be  taken  not  to  mistake 
a  slight  amount  of  suspended  matter,  frequently  resinous,  for 
other  substances  actually  soluble  in  water. 

The  still  undissolved  residue  should  be  again  removed  from 
filters  and  dishes  by  solution  in  benzene,  the  benzene  solution 
being  again  evaporated  to  dryness.  Treat  this  residue  with 
warm,  very  dilute  hydrochloric  acid,  allow  to  cool,  and  filter 
through  paper.  The  filtrate,  should  be  tested  for  alkaloids  and 
glucosides.  The  amount  extracted  by  acid,  if  any,  may  be  deter- 
mined by  weighing  the  still  undissolved  residue.  Treat  this  re- 
sidue with  several  considerable  portions  of  80  per  cent,  alcohol 
(sp.  gr.  0.8483  at  15. 6°  C.),  allowing  at  least  an  hour  for  each 
treatment.  Filter  through  paper  and  determine  by  evaporation 
the  matter  dissolved ;  this  usually  consists  of  chlorophyll  with 
one  or  more  resins,  which  may  sometimes  be  separated  by  use 
of  petroleum  benzin,  chloroform  or  similar  solvents.  Purified 
animal  charcoal  removes  chlorophyll  and  some  resins  from  alco- 
holic solution,  while  certain  other  resins  are  not  removed.  If 
camphors  were  present  in  the  plant,  the  greater  portion  will  be 
found  in  the  alcoholic  liquid. 

The  substances  undissolved  by  80  per  cent,  alcohol  may  be 
fixed  oil,  solid  fat,  wax,  and  very  rarely  a  resin;  their  separa- 


PARSONS' S  METHOD.  413 

tion  may  be  attempted  by  refrigeration  and  pressure,  or  by  use 
of  ether,  chloroform,  etc. 

Recapitulation  (portion  soluble  in  benzene  or  chloroform). 

\.  Loss  by  evaporation,  with  precautions  :  volatile  oil. 

2.  Soluble  in  water :  alkaloids,  glucosides,  organic  acids. 

0  (  Insoluble  in  water  :         )    A  77    7   . 7  .t1 

3-      Soluble  in  dilute  acids  :     Al^l°^  Posslbl7 


4. 


f  Insoluble  in  water. 
J  Insoluble  in  acids. 
1  Soluble  in  80  per  cent, 
alcohol. 


Removed  by  animal  char- 
coal :  chlorophyll,  some 


resins. 


j  Not  removed  by  animal 


(      charcoal  :  some  resins. 
(  Insoluble  in  water  :  } 

5.  •<  Insoluble  in  dilute  acids  :  V  Wax,  fats,  fixed  oils. 

(  Insoluble  in  80  per  cent,  alcohol  :  ) 

It  is  frequently  advantageous  to  extract  the  plant  with  petro- 
leum beiizin  (sp.  gr.  0.66  to  0.70,  boiling  at  about  50°  C.,  wholly 
volatile)  before  treatment  with  benzene  ;  by  reference  to  the  ac- 
companying table  of  comparative  solubilities  (p.  422)  it  will  be 
seen  that  this  treatment  may  serve  to  separate  fixed  and  volatile 
oils,  and  some  resins  ,and  colors,  from  certain  solid  fats,  wax, 
other  resins  and  colors. 

Where  benzene  of  sufficient  purity  cannot  be  had,  pure  chlo- 
roform is  the  best  substitute.  The  use  of  ether  is  objectionable 
in  this  place,  as  its  solvent  properties  are  less  distinctly  marked 
than  are  those  of  benzin,  chloroform,  and  benzene;  in  other- 
words,  more  plant  constituents  are  sparingly  soluble  in  ether 
than  in  the  above-mentioned  solvents.  Consequently  many  sub- 
stances which  should  properly  be  extracted  by  80  per  cent,  alco- 
hol will  be  sparingly  dissolved  if  ether  were  used,  while  ben- 
zene, chloroform,  and  benzin  would  have  no  perceptible  solvent 
action  upon  them  ;  tannic  acids  may  be  cited  as  instances  illus- 
trating this  point. 

YI.  Estimation  of  80  per  cent.  Alcohol  Extract. 

That  part  of  the  plant  not  dissolved  by  benzene  should  be 
dried  at  100°  C.,  and  then  completely  exhausted  by  80  per  cent. 
alcohol  (sp.  gr.  0.8483  at  15.6°  C.)  '  This  requires  from  12  to  14 
hours'  continuous  treatment  with  the  solvent.  Remove,  dry,  and 
weigh  any  crystals  or  powder  that  may  separate  upon  concentrat- 
ing and  cooling  the  alcoholic  percolate.  Make  the  clear  liquid 


414  PLANT  ANAL  VSIS. 

to  a  definite  volume  (say  200  e.c.),  by  adding  more  80  percent, 
alcohol. 

AN  ALIQUOT  PART  (usually  20  c.c.)  of  this  volume  of  liquid 
is  evaporated  to  dryness  for  weight  (//i)  of  organic  matter  with 
ash,  the  residue  then  ignited  for  weight  (n)  of  ash,  to  find  by 
difference  (m  —  ri)  the  amount  (o)  of  organic  matter  in  VI. 
ANOTHER  EQUAL  ALIQUOT  PART  (20  c.c.)  is  evaporated  to  remove 
all  alcohol,  treated  with  water,  filtered,  and  the  filtrate  and  wash- 
ings evaporated  to  dryness  to  find  the  weight  (p)  of  organic 
matter  and  ash  that  are  soluble  in  water,  the  residue  then  ignited 
for  weight  (q)  of  ash  that  is  soluble  in  water.  Then  p  —  q  =  r, 
the  amount  of  organic  matter  (in  VI.)  soluble  in  water. 

If  the  plant  contain  much  sugar  or  much  tannin,  it  will  be 
desirable  to  proceed  now,  in  separation  by  water,  as  directed 
further  on  for  " the  second  way"  Otherwise  proceed  in  sepa- 
ration by  absolute  alcohol,  in  "  the  first  way"  as  follows  :  THE 
REMAINING  ALIQUOT  PART  (160  c.c.)  of  the  clear  alcoholic  liquid 
should  be  evaporated  carefully  to  dryness,  the  residue  pulverized 
and  treated  with  several  considerable  portions  of  absolute  alco- 
hol (sp.  gr.  0.7938  at  15.6°  C.) 

i 

A.  Soluble  in  Absolute  Alcohol  (from  the  portion  by  80$  alcohol). 

a.  Soluble  in  water. 

a! .  Precipitated  by  subacetate  of  lead. 

Tannin  and    most  organic  acids ;    some   extractives ; 
some  inorganic  acids  of  the  ash.     Weigh  in  Gooch's 
filter,  ignite  cautiously,  and  again  weigh ;  loss  equals 
organic  matter  precipitated. 
a".  Not  precipitated  by  subacetate  of  lead. 

Alkaloids,  glucosides,  some  extractives  and  colors. 
Determine  weight  by  difference  between  a  and  af. 

b.  Insoluble  in  water. 

br.  Soluble  in  dilute  hydrochloric  acid. 

Alkaloids,  glucosides  (rarely),  some  extractives.     De- 
termine weight  by  difference  between  b  and  ~b" . 
b".  Insoluble  in  dilute  hydrochloric  acid, 
b'" '.  Soluble  in  dilute  ammonium  hydrate. 

Most  acid  resins,  some  colors.     Determine  weight  by 

difference  between  b"  and  ~b"" . 
b"".  Insoluble  in  dilute  ammonium  hydrate 

Neutral   resins,   some    colors,    albuminoids  (in  some 

seeds). 
Redissolve  in  alcohol,  evaporate,  and  weigh. 


PARSONS'S  METHOD.  415 

B.  Insoluble  in  Absolute  Alcohol  (from  portion  by  80$  alcohol). 

c.  Soluble  in  water. 

c'.  Precipitated  l)y  subacetate  of  lead. 

Some  colors,  extractives,  albuminoids  (rarely),  organic 
acids,  and  inorganic  acids  of  the  ash.  Weigh  in 
Gooch's  iilter,  ignite  cautiously,  and  again  weigh ; 
loss  equals  organic  matter  precipitated. 

c".  Not  precipitated  oy  subacetate  of  lead. 

Alkaloids,  glucosides,  glucose,  sucrose,  some  extrac- 
tives. Determine  by  difference  between  c  and  c' '. 
Eemove  Pb  by  H2S,  H2SO4,  Na2CO3,  or  other 
means,  and  titrate  for  sucrose  and  glucose. 

d.  Insoluble  in  water. 

d'.  Soluble  in  dilute  hydrochloric  acid. 

Some  alkaloids  and  glucosides.    Determine  by  diffeiv 

ence  between  d  and  d". 
d".  Insoluble  in  dilute  hydrochloric  acid. 

Few  resins,  some  extractives  and  color  substances. 
Dissolve  in  alcohol,  evaporate,  and  weigh  in  a  tared 
dish. 

"  The  second  way":  primary  division  of  constituents  in  VI.,  by  solubility 
in  water. — In  some  cases  it  may  be  preferable  to  use  the  following  method  for 
analysis  of  the  80  per  cent,  alcohol  extract ;  it  is  more  desirable  when  the 
plant  examined  contains  a  considerable  amount  of  sugars,  tannic  acid,  etc. 

Alcohol  Extract,  dilute  to  200  c.c.  with  80  per  cent,  alcohol.— 1.  In  20  c  c. 
determine  total  organic  matter  and  ash.  Then,  2,  in  20  c.c.  determine  total 
organic  matter  and  anh  that  are  soluble  in  water,  and,  by  difference,  total  or- 
ganic matter  insoluble  in  water,  as  directed  in  "  the  first  way." 

3.  Evaporate  the  remaining  160  c.c.  to  dryness,  treat  with  water,  filter,  and 
make  the  filtrate  measure  160  c.c.     Reserve  the  insoluble  matter  on  the  filter 
for  examination  (10). 

4.  In  20  c.c.  of  the  aqueous  solution  estimate  the  tannin.1 

5.  Precipitate  20  c.c.  by  normal  acetate  of  lead,  and  determine,  as  before 
described,  the  amount  of  organic  matter  after  drying  at  100°  to  120°  C.     This 
precipitate  will  contain,  if  the  substances  are  present  in  the  plant,  tannic,  gal- 
lic, and  most  other  organic  aci'ls,  some  colors,  rarely  albuminous  substances, 
some  extractives,  and  most  inorganic  acids  of  the  ash.     Determine,  by  differ- 
ence, the  amount  not  precipitated  by  this  treatment. 

6.  In  20  c.c.  determine  in  like  manner  the  amount  precipitated  by  basic 
acetate  ("  subacetate  ")  of  lead.     This  reagent  precipitates  a  greater  number  of 
acids,  colors,  and  extractives  than  are  precipitated  by  the  normal  acetate,  hence 
it  is  frequently  possible  to  estimate  such  substances  by  subtracting  the  amount 
precipitated  by  one  reagent  from  the  amount  precipitated  by  the  other     To  the 
filtrate  add  a  slight  excess  of  dilute  hydrochloric  acid,  boil  gently  for  half  an 
hour,  and  determine  in  the  liquid  total  glucose  by  use  of  Fehling's  solution. 

i  For  this  estimation  methods  are  given  in  the  article  on  Tannins  in  this 
work.  Mr.  Parsons  advised  the  gravimetric  method  of  CARPENI  (1875:  Jahr. 
der  Chem.,  9ft9:  Chem.  News,  31,  282).  Precipitate  by  ammoniacal  acetate 
of  zinc,  use  a  Gooch's  filter,  wash  the  precipitate  with  very  weak  ammonia,  dry 
at  120°  C.,  weigh,  ignite  cautiously,  again  weigh.  The  loss  by  ignition  equals 
tannic  acid,  in  absence  of  certain  interfering  substances. 


4i6  PLANT  ANAL  YSIS. 

7.  Precipitate  20  c.c.  by  subacetate,  exactly  as  in  6,  and  use  the  precipitate 
as  a  duplicate  to  check  the  amount  there  estimated.     To  the  filtrate  add  a  very 
slight  excess  of  solution  of  carbonate  of  sodium,  filter  from  the  carbonate  of 
lead,  wash  well  with  water  containing  a  little  alcohol,  and  in  the  filtrate  esti- 
mate actual  glucose.     If  the  glucose  thus  found  is  appreciably  less  than  that  in 
i),  subtract  it  from  that  amount;  this  glucose  maybe  due  to  the  presence  in  the 
plant  of  sucrose  or  some  glucoside.     If  due  to  sucrose,  the  amount  of  the  latter 
may  be  found  by  multiplying  this  residual  glucose  by  0.95;  if  to  a  glucoside,  a 
fit  subject  for  an  extended  investigation  is  presented.    The  properties,  formula, 
and  decomposition  products  of  the  newly  found  glucoside  should  be  carefully 
studied. 

8.  Precipitate  20  c.c.  with  subacetate  of  lead,  as  in  6  and  7,  employing  the 
precipitate  as  material  from  which  to  separate  organic  acids,  after  removal  of 
lead  by  sulphuretted  hydrogen.     Acidulate  the  filtrate  with  sulphuric  acid,  add 
an  equal  volume  of  alcohol,  allow  to  stand  two  hours,  filter,  wash  the  precipi- 
tate with  50  per  cent,  alcohol,  and  evaporate  the  filtrate  until  all  alcohol  has 
been  dissipated.     Test  the  acid  solution  for  alkaloids,  glucosides,  sugars,  ex- 
tractives. 

9.  Reserve  the  remaining  40  c.c.  for  duplicating  any  unsatisfactory  deter- 
minations. 

10.  The  residue  mentioned  in  3  as  insoluble  in  water  may  contain  resins, 
albuminoids  (especially  from  seeds),  colors,  alkaloids,  glucosides.     Dilute  acids 
remove   alkaloids  and  some    glucosides;  dilute  ammonia  water  will   remove 
some  resins,  colors,  and  glucoxides.     Any  still  insoluble  residue  probably  con- 
tains albuminous  or  resinous  substances." 

YII.  Estimation  of  Cold  Water  Extract. 

That  part  of  the  plant  remaining  insoluble  after  treatment 
with  alcohol  should  be  dried  at  110°  C.  and  completely  extract- 
ed by  cold  water.  When  the  plant  contains  considerable  mu- 
cilaginous matter  this  is  best  removed  by  placing  the  sub- 
stance in  a  flask  or  graduated  cylinder,  and  then  adding  a  mea- 
sured volume  of  cold  water.  Allow  to  macerate,  with  frequent 
agitation,  for  from  6  to  12  hours,  then  filter  through  line  washed 
linen,  and  evaporate  an  aliquot  portion  of  the  solution.  In  this 
residue  determine  total  organic  matter  and  ash.  This  residue 
usually  contains  little  but  gum  /  in  analysis  of  fruits  and  fleshy 
roots,  pectin  bodies,  salts  of  organic  acids,  rarely  a  substance  re- 
sembling dextrin,  and  small  amounts  of  albuminous  substances 
and  coloring  matter.  Usually  the  separation  of  these  substances 
is  very  difficult.  The  unevaporated  liquid  should  be  used  for 
such  qualitative  reactions  as  are  necessary  to  show  the  nature  of 
the  substances  extracted.  The  insoluble  residue  should  be  well 
washed  with  water,  transferred  to  a  crucible,  and  completely 
dried  at  110°  C.  This  residue  should  then  be  weighed. 

VIII.  Estimation  of  Acid  Extracts. 

The  dried  residue  insoluble  in  cold  water  should  be  trans- 
ferred to  a  beaker  containing  500  c.c.  of  water  and  5  c  c.  of  con- 
centrated sulphuric  acid  (sp.  gr.  1.84).  Boil  for  6  hours  on  a 


PARSONS' S  METHOD.  417 

gauze  support,  adding  water  to  keep  the  volume  of  liquid  un- 
changed ;  if  the  substance  be  very  starchy  a  longer  boiling  may 
be  necessary.  This  treatment  will  convert  starch  and  its  amor- 
phous isomers  to  dextro-glucose,  and  will  occasionally  remove 
some  salt  of  an  organic  acid,  with  usually  traces  of  albuminous 
and  indeterminate  substances. 

The  total  amount  extracted  may  be  found  by  washing,  drying 
at  110°  C.,  and  weighing  the  yet  insoluble  residue,  and  subtract- 
ing the  weight  from  the  one  taken  after  extracting  with  cold 
water.  The  amount  of  starch  and  isomers  may  be  found  by 
determining  in  a  given  volume  of  the  acid  filtrate  the  amount  of 
glucose,  using  Fehling's  solution ;  the  glucose  thus  found  multi- 
plied by  0.9  equals  starch  and  isomers.  The  total  extract  minus 
starch  and  isomers  equals  acid  extract  not  starch.  '  This  includes 
a  small  amount  of  ash,  which  may  be  approximately  determined 
by  evaporating  and  igniting  a  known  volume  of  the  solution. 

Where  it  is  wished  to  separate  the  extracted  matter  from  the 
sulphuric  acid,  boil  the  liquid  with  an  excess  of  powdered  barium 
carbonate  until  no  acid  reaction  remains.  Filter  and  evaporate 
to  dry  ness.  The  residue  consists  chiefly  of  hydrated  dextro- 
glucose  (C6H12O6.H2O),  with  some  ash. 

IX.  Estimation  of  Alkali  Extract. 

Wash  well  and  dry  at  110°  C.  the  residue  from  treatment 
with  acid,  and  record  its  weight.  Boil  this  residue  for  two 
hours  with  500  c.c.  of  a  solution  containing  20  grams  of  sodium 
hydrate  to  the  liter.  Filter  through  fine  washed  linen,  and  wash 
the  residue  thoroughly  with  hot  water,  alcohol,  and  ether. 
Transfer  it  to  a  weighed  crucible,  dry  at  110°  to  120°  C.,  and 
weigh  the  residue  as  crude  fibre  and  ash  •  this  weight  subtracted 
from  the  previous  one  shows  the  total  alkali  extract.  This  ex- 
tract is  largely  albuminous  matter  and  various  modifications  of 
pectic  acid,  Fremy's  " cutose"  and  various  coloring,  humus,  and 
decomposition  compounds,  in  small  amounts.  Most  of  the  ex- 
tracted substances  may  be  precipitated  by  excess  of  an  acid  with 
or  without  the  presence  of  alcohol. 

X.  Cellulose. 

The  crude  fibre  from  IX.  should  be  treated  with  from  50  to 
100  c.c.  of  U.  S.  Ph.  solution  of  chlorinated  soda  and  allowed  to 
stand  twenty-four  hours.  If  not  then  bleached  white,  slightly 
acidulate  with  hydrochloric  acid  and  set  aside  for  another  day. 
Filter  through  fine  linen  or  Gooch's  filter,  wash  with  hot  water. 


418  PLANT  ANALYSIS. 

dry  at  110°  to  120°  C.,  and  weigh,  ash-free,  as  cellulose.     The 
loss  of  weight  by  this  treatment  state  as  lignose  and  color. 

Recapitulation  of  Parson^  s  Method. 

I.  Sampling,  pulverization,  and  preservation  of  an  air-dry 

portion  in  constant  condition  for  an  analysis. 
II.  Estimation  of  moisture  by  loss  at  100°-120°  C. 
III.  Estimation  of  Ash. 

a.  Portion  of  the  ash  soluble  in  water. 

b.  Insoluble  in  water;    soluble  in  dilute  hydrochloric 

acid. 

c.  Insoluble  in  water  or  in  the  acid  ;  soluble  in  sodium 

hydrate  solution. 

IV".  Estimation  of  the  total  nitrogen.  For  check  on  results ; 
for  calculation  of  albuminoids  after  estimation  of 
alkaloids,  etc. 

Y.  ESTIMATION  OF  PORTION  SOLUBLE  IN  BENZENE  (OB  CHLORO- 
FORM). 

1.  Portion  of  benzene  extract  vaporized  with  benzene : 

volatile  oils  (camphors). 

2.  Portion  of  benzene  extract  soluble  in  water :  alka- 

loids, glucosides,  organic  acids. 

o  j  Not  soluble  in  water,  |          A. Ikaloids,  possibly  glu- 
'  \  soluble  in  dilute  acid  :  j  cosides. 

Removed  bv  animal 

Not  soluble  in  water  )    !  "'         charcoal:  "cMoro- 

pliyii,  sortie  resins. 
Not  removed  by  the 
charcoal :       some 


4.  •<  or  the  acid.     Soluble  >  -j 
(  in  alcohol  of  80$.         )      ft 


resins. 

(  Not  soluble  in  water 
5.  •<  or  the  acid,  or  in  al-  V       Waxes,  fats,  fixed 

(  cohol  of  80$  :  ) 

VI.  ESTIMATION  OF  PORTION  SOLUBLE  IN  ALCOHOL  OF  80$  (after 
removal  of  Y.)  The  solution  is  made  up  to  a  defi- 
nite volume  (200  c.c.)  IN  TWO  EQUAL  ALIQUOT  PARTS 
(20  c.c.  each)  residues  are  obtained  to  furnish  (1)  the 
amount  of  organic  matter,  (2)  the  amount  of  organic 
matter  soluble  in  water,  thence  the  amount  of  or- 
ganic matter  insoluble  in  water. 

IN  "  THE  FIRST  WAY  "  the  constituents  of  YL,  in  the  re- 
maining 160  c.c.,  are  primarily  divided  according  to 
their  solubility  in  absolute  alcohol,  then  by  further 
treatment,  as  follows : 


PARSOXS'S  METHOD.  419 

A.  Soluble  in  absolute  alcoTiol. 

a.  Soluble  in  water.     Weight  obtained. 
a' '.  Precipitated  by  subacetate  of  lead. 

Tannin  and  most  organic   acids;    some    ex- 
tractives; some  inorganic  acids  of  the  ash. 
Weight  of  all  obtained. 
a" .  Not  precipitated  by  subacetate  of  lead. 

Alkaloids,  glucosides,  extractives,  colors, 
a  —  af  =.  a" . 

b.  Insoluble  in  water.      Weight  obtained. 
V .  Soluble  in  dilute  hydrochloric  acid. 

Alkaloids,  rarely  glucosides,  extractives. 

£_£"=:&'.    ^ 

~b" .  Insoluble  in  dilute  hydrochloric.     Weight  taken. 
b"1 '.  Soluble  in  dilute  ammonium  hydrate. 
Most  acid  resins,  some  colors. 
I"  —  I""  -  I'". 

V" .  Insoluble  in  the  ammonia.     Weight  taken. 
Neutral  resins,  some  colors,  albuminoids. 

B.  Insoluble  in  absolute  alcohol. 

c.  Soluble  in  water. 

c'.  Precipitated  by  subacetate  of  lead. 

Colors,  extractives,  rarely  albuminoids,  organic 

and  inorganic  acids.     Weigh. 
c" .  Not  precipitated  by  subacetate  of  lead. 

Alkaloids,  glucosides,  glucose,  sucrose,  extrac- 
tives. 

c  —  c'  =  c" .     Estimate  sugars. 

d.  Insoluble  in  water. 

df.  Soluble  in  dilute  hydrochloric  acid. 

'  Alkaloids,  glucosides.     d  —  d"  —  d'. 
d" .  Insoluble  in  dilute  hydrochloric  acid. 

Few  resins,  extractives,  colors.  Weigh. 
IN  "THE  SECOND  WAY"  the  constituents  of  VI.,  taken  in 
the  remaining  160  c.c.  of  80$  alcohol  solution,  are  pri- 
marily divided  according  to  their  solubility  in  water, 
then  by  other  treatment,  as  follows :  (3)  Evaporate 
to  dryness,  add  water,  reserve  the  residue  (10),  and 
make  the  filtrate  up  to  160  c.c. 

(4)  In  20  c.c.  estimate  tannin. 

(5)  In  20  c.c.  estimate  total  precipitate  by  lead  normal 
acetate.     Tannins,  acids  (inorganic  and  organic), 
colors,  extractives. 


420  PL  A  NT  ANAL  YSIS. 

(6)  In  20  c.c.  estimate  total  precipitate  by  lead  basic 
acetate.     Compare  precipitate  with  that  in  (5). 
In  filtrate  estimate  the  total  glucose  of  sugars  and 
glucosides. 

(7)  In  20  c.c.  duplicate  the  precipitation  of  (6).      In 
filtrate  estimate  the   actual   glucose.      Compare 
with  total  glucose. 

(8)  In  20  c.c.  triplicate  the  precipitation  of  (6).     Ex- 
amine the  precipitate  for  alkaloids,  glucosides, 
sugars,  extractives. 

(9)  Use  the  remaining  40  c.c.  for  additional  exami- 
nations. 

(10)  The  residue  left  in  operation  3  may  be  tested 
for  reams y  albuminoids,  colors,  alkaloids,  gluco- 
sides. 

VII.  ESTIMATION  OF  THE  PORTION  SOLUBLE  IN  COLD  WATER  (after 
removal  of  V.  and  YI.)  Examine  as  directed  in  the 
text,  making  up  the  filtrate  to  a  definite  volume,  and 
taking  aliquot  parts  (1,  2,  3,  4,  etc.)  for  determina- 
tions and  tests.  In  (1)  determine  total  solids,  and 
then  the  ash,  to  find  the  total  organic  substances. 
Gums,  pectous  substances,  salts  of  organic  acids, 
dextrins,  soluble  starches,  albumens,  colors.  Examine 
by  solubilities,  iodine  test,  estimation  of  nitrogen,  etc. 
The  residue  from  solution  VII.,  dried  at  110°  C.,  is 

weighed. 

VIII.  ESTIMATION  OF  PORTION  SOLUBLE  IN  BOILING-  DILUTE  ACID 
(after  removal  of  Y,  VI.,  and  VII.)  The  weight 
of  the  washed  residue  obtained  for  estimation  of 
the  total  solids  of  VIII.  Starches  estimated  by 
determination  of  glucose  with  Fehling's  solution, 
first  examining  for  interfering  extractives  of  a  reduc- 
ing power.  An  aliquot  portion  of  the  liquid,  freed 
from  the  sulphuric  acid,  is  tested  in  portions  quali- 
tatively. Small  amounts  of  albuminoids  may  be 
found. 

IX.  ESTIMATION  OF  PORTION  SOLUBLE  IN  ALKALI-- WATER  (after 
removal  of  portions  Y.  to  VIII.)  Take  weight  of 
insoluble  washed  residue,  for  estimation  of  total  sol- 
ids. Album,ens,  forms  of  pectin,  humus,  decomposi- 
tion products,  colors. 

X.  ESTIMATION  OF  THE  RESIDUE  LEFT  BY  SOLVENTS  Y.  to  IX. 
Cellulose,  lignose,  colors,  ash.  Estimate  from  sepa- 
ration by  chlorinated  soda  solution. 


PARSONS 'S  METHOD.  421 

Remarks. l 

It  is  advisable  to  determine  always,  in  addition  to  what  has  already  been 
directed,  the  amounts  extracted  directly  from  the  sample  by  water,  ether,  alcohol 
of  various  percentages,  methyl  alcohol,  benzin,  chloroform,  carbon  disulphide, 
etc.  In  each  extract  estimate  total  organic  matter  and  ash,  and  determine 
qualitatively,  and  quantitatively  when  possible,  its  constituents,  by  treating 
with  such  solvents  and  reagents  as  are  indicated.  Each  extract  being  com- 
posed of  certain  distinct  substances,  it  is  necessary  to  account  for  them  in 
every  case. 

The  amounts  present  of  some  constituents  may  be  found  by  subtracting 
the  weight  extracted  by  some  one  solvent  from  the  weight  extracted  by  some 
other.  It  will  be  seen  that  this  is  a  method  of  limited  applicability,  which  can 
only  be  applied  in  those  cases  where  the  difference  between  the  solvent  action 
of  the  two  liquids  is  very  sharply  defined.  Certain  special  methods  for  the  esti- 
mation of  single  constituents  may  be  used,  care  being  taken  that  all  interfering 
substances  be  first  removed.  The  methods  of  preparation  of  known  substances 
as  given  in  HUSEMANN'S  "  Pflanzenstoffe,"  and  to  a  considerable  extent  in 
"  Watts's  Dictionary,"  may  serve  as  suggestions  for  work.  Treatment  with  ben- 
zene, 80  per  cent,  alcohol,  and  water,  removes  from  nearly  all  plants  the  con- 
stituents of  greatest  chemical  and  medicinal  interest,  but  in  analyses  of  grains, 
fodder,  and  food  materials,  those  compounds  extracted  by  dilute  acids  and  alka- 
lies have  great  value.  There  are  substances  in  plants,  seemingly  isomers  of 
starch  and  cellulose,  which  have  properties  more  or  less  resembling  those  of 
cellulose,  and  are  changed  by  boiling  with  dilute  acids  to  glucose.  In  absence 
of  an  established  nomenclature  it  has  seemed  best  to  use  the  terms  "starch 
isomers"  or  " amylaceous  cellulose "  for  these  substances,9  while  those  consti- 
tuents, not  albuminous,  which  are  removed  by  dilute  alkali  have  been  termed 
"alkali  extract."  These  substances  have  been  investigated  by  various  chemists, 
but  no  definite  and  authoritative  nomenclature  has  yet  been  adopted.  THOM- 
SEtf  gives  the  name  "  holz-gummi,"  3  wood-gum,  to  a  white  substance  extracted 
from  plants  by  dilute  sodium  hydrate,  while  FREMY  regarded  these  various  com- 
pounds as  modifications  of  pectic  acid,  pectin,  and  "cellulose  bodies."4 
Starch  also  may  exist  in  some  seeds  (as  of  sweet  corn)  in  a  form  soluble  in 
water.5 

It  will  be  seen  that  the  field  for  investigation  is  limitless,  and  that  there 
is  great  need  for  improved  methods  for  proximate  analysis.  The  analyst  will 
find  that  a  study  of  any  common  plant  will  require  of  him  much  more  than 
unthinking,  mechanical  habits  of  manipulation,  while  every  careful  investi- 
gation will  reveal  to  him  some  constituents  deserving  more  full  and  accurate 
study. 


1  By  Henry  B.  Parsons. 

3  U.  S.  Dept.  of  Agric.  Report,  1878,  p.  189. 


3Jonr.  prnk.  Chem.,  19,  146. 

*Compt.  rend..  83,  1136;  Jour.  Chem.  Soc..  31,  229(1877). 

6  U.  S.  Dept.  of  Agric.  Report,  1878,  pp.  153-155. 


422 


PLANT  ANALYSIS. 


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DRA  GENDORFF'S  ME THOD.  423 

OUTLINE  OF   DRAGENDORFF' s  METHOD  OF  PLANT  ANALYSIS/ 

For  the  systematic  analysis  30  to  50  grams  may  usually  be 
taken.  From  2  to  5  grams  are  dried  at  100°-110°  for  total 
moisture ;  and  usually  another  portion,  not  above  30°  C.,  for 
amount  of  loss.  The  material  for  the  systematic  analysis  to  be 
powdered,  sampled,  mixed,  and  very  finely  pulverized  for  sol- 
vents. Yery  hard  bodies  are  dried  at  100°  to  110°  C.  before 
pulverizing.  Fatty  bodies  may  be  lirst  treated  with  the  petroleum 
benziri.  lor  ignition  pulverize  very  line,  and  if  need  be,  after 
partial  ignition,  pulverize  again.  To  promote  combustion  am- 
monium nitrate  may  be  added,  or  ignited  and  weighed  ferric  ox- 
ide may  be  introduced.  Powdered  glass  or  washed  sand  may  be 
intermixed.  The  carbon  dioxide  of  the  ash  is  to  be  determined. 
Special  methods  are  used  for  the  full  quantitative  estimations  of 
distinct  substances. 

I.  SOLUTION  BY  PETROLEUM  BENZIN  (petroleum-ether,  petrole- 
um spirit). — This  solvent  to  boil  to  the  last  at  45°  G.  and  leave 
no  residue.  Use  10  c.c.  for  each  gram  of  the  dry  plant  pow- 
der. Macerate  eight  days,  shaking  daily.  Aromatic  fresh  plants 
may  be  treated,  without  previous  drying,  by  fine  division,  and  by 
percolation  with  the  solvent.  Receive  in  a  graduated  separator, 
and  take  off  aliquot  volumes  for  examination  and  for  weight  of 
total  dissolved  substances. 

To  evaporate  the  solvent  from  essential  oils  and  other  vola- 
tile matters,  almost  without  waste  of  the  latter,  place  2  the  solu- 
tion in  a  small,  shallow  dish,  which  is  to  be  set  within  a  wide- 
mouthed  jar,  this  being  so  connected  that  a  current  of  dried  air 
is  drawn  over  the  surface  of  the  solution.  The  air  is  drawn 
through  chloride  of  calcium  tubes,  one  of  which  is  placed  before 
and  one  beyond  the  jar  containing  the  solution,  so  that  there  can. 
be  no  backward  diffusion  of  moist  air.  The  jar  is  closed  air- 
tight by  a  stopper  admitting  entrance  and  discharge  tubes,  the 
•entrance  tube  reaching  nearly  to  the  surface  of  the  benzin  solu- 
tion. The  air  is  drawn  at  the  desired  rate  by  an  aspirator,  one 
acting  by  the  discharge  of  water  from  a  large  closed  bottle 
or  jar. 

'•  References  to  publication  of  DragendorfF s  work  are  given  on  p.  407.  This 
outline  is  by  no  means  a  substitute  for  Dr.  DragendorfF s  book  on  the  chemistry 
and  analysis  of  plants.  But  the  outline  of  his  plan  of  separations  is  presented 
for  the  convenience  of  a  compact  form,  and  as  suggestion  for  instituting  various 
analytical  operations  on  vegetable  tissues. 

*  This  method  of  evaporation  in  a  current  of  dry  air  was  used  by  OSSE, 
who  reports  control-analyses  by  it,  1876:  Archiv  d.  Phar.  [3]  7,  104;  Jour. 
Chem.  Soc.,  29,  759;  Dragendorffs  "  Plant  Anal.,"  by  Greenish,  p.  21. 


424  PLANT  ANALYSIS. 

Fats  may  be  treated  with  alcohol  and  observed  with  the 
microscope.1 

Glycerides  may  be  saponified  for  separation  [see  pp.  274, 
265,  etc.] 

Alkaloids  subjected  to  general  tests  [pp.  33,  42,  53]. 

Ethereal  oils  tested  by  solubilities,  sensible  properties,  re- 
actions. 

Volatile  acids  recognized  by  acidity  or  by  forming  salts. 

Chlorophyll,  by  optical  examination.2 

II.  SOLUTION  BY  ETHEK. — This  solvent   to  be   prepared   as 
nearly  as  possible  free  from  alcohol  and  from  water  (so  as  not  to 
take  up  tannin).     It  is  applied  to  the  drug  or  vegetable  matter 
previously  exhausted  by  petroleum  benzin,  washed  with  the  lat- 
ter, and  dried.     For  1  gram  use  5  to  10  c.c.  of  the  ether.      Ma- 
cerate in  a  graduated  cylinder  seven  or  eight  days.     Take  off 
aliquot  volumes  for  examination.      Evaporate  the   ether  by  a 
current  of  dried  air,  as  directed  for  the  benzin.     Test  portions 
by  solubilities  in  (a)  water,  (b)  alcohol   (absolute),   (c)   alkali. 
The  ether-soluble  portion  may  contain  benzoic,  salicylic,  and  gal- 
lic acids,  salicin  and  other  glucosides,  alkaloids,  resins,  hema- 
toxylin,   etc.     For   estimation   of  total  ether-soluble  fixed  sub- 
stances an  aliquot  part  is  evaporated  and  dried  at  110°  C.     [Fur- 
ther see  the  articles  Alkaloids,  Benzoie  Acid,  etc.     Resins  are 
found  in  the  part  insoluble  in  water.     Compare  p.  278.] 

III.  SOLUTION  BY  ABSOLUTE  ALCOHOL  (following  solvents  I., 
II.) — For  1  gram  of  the  material  10  c.c.  of  the  sol  vent.    Macerate 
five  to  seven  days,  restoring  loss,  then  filtering  through  paper  wet 
with  alcohol.     Evaporate  an  aliquot  volume,  and  dry  at  110°  C. 
for  weight.     Evaporate  other  portions,  without  heat,  in  vacuum, 
and  dry  over  sulphuric  acid.    A  residue,  obtained  as  last  directed, 
is  to  be  treated  with  water,  in  measured  proportion,  filtered,  the 
filtrate  evaporated  to  constant  weight  at  110°  C.,  for  weight  of 
all  water-soluble  matters  in  III.     Other  portions  of  the  aqueous 
solution  are  taken  for  the  estimation  of  tannins  and  for  sugars. 
A  portion  of  the  residue  (III.),  undissolved  by  water,  is  gently 
dried  and  treated  with  ammonia  water  dilute  (1 :  50),  the  ammonia 
solution  acidulated  with  acetic  acid,  and  the  precipitate,  if  any,, 
after  concentration,  examined  for  phlobaphene,  which  may  be 
estimated  in   this  way  [see  Phlobaphene,  under  Tannins].     Por- 
tion III.  may  contain  resins,  alkaloids,  glucosides,  bitter  prin- 
ce 


1  See  HEINTZ:  Ann.  Ptiys.  Chem.  (Pogg.),  92,  588;  Phar.  Jour.  Trans.  [1] 
15,  425.     GREENISH:  Phar.  Jour.  Trans.  [8]  10,  909.     This  work,  p.  297. 

2  Dragendorff,  English  ed.,  p.  19. 


'-'"N/VERSITY 


DRAGENDORFFS  METHOD.  42$ 

The  water-soluble  portions  of  II.  (the  ether  -extract)  and  of 
III.  (the  alcohol-extract)  may  be  treated  by  imm-iscible  solvents^ 
applied  first  to  the  watery  liquids  made  acidulous  with  sulphuric 
acid,  and  then  applied  to  the  same  liquids  made  ammoniacal  with 
ammonia.  [See  this  work,  pages  33  and  after  ;  and  the  author's 
"  Outlines  of  Proximate  Organic  Analysis,"  p.  136.]  As  immis- 
cible solvents,  petroleum  benziu,  benzene  (boiling  constant  at 
81°  C.),  and  chloroform  are  recommended.  The  following  re- 
sults are  indicated  :  By  petroleum  benzin  from  acid  solution  — 
Absinthin,  Capsicum,  Hop  bitter,  Piperin,  Salicylic  acid.  By 
benzene  from  acid  solution  —  Absinthin,  Berberine,  Caffeine, 
Caryophyllin,  Cascarillin,  Colchicine,  Colocynthiri,  Cubebin, 
Daphnin,  Elaterin,  Ericolin,  Gratiolin,  Menyanthin,  Populinr 
Quassin,  Santonin.  By  chloroform  from  acid  solution  —  JEs- 
culin,  Benzoic  acid,  Cinchonine,  Colchicine,  Convallamarin,  Di- 
gitalein,  Helleborin,  Narceine,  Physalin,  Picrotoxin,  Quinidine, 
Theobromine,  Saponin,  Senegin,  Solanidin,  Syringin.  (Before 
making  alkaline,  the  dissolved  chloroform  is  washed  out  with  a 
little  petroleum  benzin.)  By  petroleum  benzin  ^rom  alkaline 
aqueous  solution  —  Brucine,  Capsicum,  Conine,  Emetine,  Lobe- 
line,  Morphine,  Nicotine,  Sabadilline,  Sabatrine,  Sparteine, 
Strychnine  (traces),  Trirnethylarnme.  By  benzene  from  alka- 
line solution  —  Aconitine,  Atropine,  Cinchonme  (traces),  Co- 
deine, Delphinine,  Gelsemine,  Hyoscyamine,  Physostigmine, 
Pilocarpine,  Nareotine,  Quinidine,  Taxine.  By  chloroform 
from  alkaline  solution—  Cinchonine,  Morphine  (traces),  Papa- 
verine,  Narceine.  By  amyl  alcohol  from  alkaline  aqueous  so- 
lution (following  previous  solvents)  —  Morphine,  Salicin,  Sola- 
nine. 

[Tests  for  a  glncoside,  by  fermentation,  are  indicated  in  the 
article  Tannins  in  this  work.  Estimation  of  alkaloids,  p.  44, 
and  under  the  several  alkaloids.] 

IY.  SOLUTION  IN  WATEK.  —  The  residue  insoluble  in  absolute 
alcohol  (III.)  is  dried  and  treated  with  10  parts  of  water,  by  48 
hours'  digestion,  then  filtered  through  the  filter  previously  used. 
The  filter  should  be  washed  with  water,  and  the  washings  exam- 
ined separately.  An  aliquot  volume  (10  to  20  c.c.)  of  the  fil- 
trate is  evaporated,  and  dried  at  110°  C.,  for  weight  of  total  sub- 
stances in  IV.  To  another  aliquot  portion,  10  to  20  c.c.,  add 
2  c.c.  absolute  alcohol,  leave  24  hours  in  a  cool  place,  filter  on  a 
tared  filter,  wash  with  66$  alcohol,  dry,  and  weigh.  Find  the 
weight  of  ash  in  each  of  the  two  portions  last  weighed.  In  IV. 
may  be  found  pectous  substances,  albumens,  inulin,  dextrines, 
sugars,  acids,  saponin.  A  precipitate  by  lead  acetate  will 


426  PTOMAINES. 

contain  the  acids,  with  mineral  acids.  Sugars  here  are  to  be 
estimated.  A  portion,  before  and  after  obtaining  IV.,  may  be 
subjected  to  estimation  of  nitrogen,  when  consideration  is  given 
to  the  presence  of  amrnoniacal  salts,  amides,  alkaloids,  nitrates, 
etc.  (Dragendorff,  paragraph  97).  Albumen  is  estimated  by  pre- 
cipitation with  tannin  or  from  the  amount  of  nitrogen. 

Y.  SOLUTION  IN  ALKALI  WATER. — For  1  part  residue  not  dis- 
solved in  IY.  take  10  parts  of  a  0.1  to  0.2$  solution  of  sodium 
hydrate.  Macerate  24  hours.  Filter  an  aliquot  volume,  satu- 
rate with  acetic  acid,  add  alcohol  of  90$,  leave  24  hours  in 
the  cold.  Collect  the  precipitate  on  a  tared  iilter,  wash  with 
75$  alcohol,  dry,  and  weigh.  Ignite  and  weigh  the  ash.  Al- 
bumens and  pectous  substances  are  contained. — The  residue 
insoluble  in  alkali  is  apt  still  to  retain  traces  of  nitrogen  com- 
pounds. 

YI.  SOLUTION  IN  ACIDULATED  WATER  (after  removal  of  I.  to 
Y.) — The  residue  not  soluble  in  Y.,  washed,  is  treated  with  a 
1$  solution  of  hydrochloric  acid.  It  is  found  by  a  microscopic 
examination  of  the  original  material,  whether  it  contains  starch 
or  not.  Oxalate  of  calcium  may  be  separated  and  estimated, 
digesting  with  the  acid  for  24  hours  at  30°  C.  In  a  measured 
quantity  of  the  liquid,  neutralize  with  ammonia,  add  acetate  of 
sodium  to  react  with  all  the  hydrochloric  acid,  and  set  aside  for 
the  calcium  oxalate  to  form,  for  gravimetric  determination  (as 
calcium  carbonate). 

VII.  THE  INSOLUBLE  RESIDUE  from  VI.  is  washed,  dried,  and 
weighed.  Treated  with  chlorine,  and  weight  of  residue  found, 
the  difference  represents  lignin  and  incrusting  substances ;  the 
remainder  contains  the  cellulose,  which  is  examined  microsco- 
pically, and  the  ash. 

PROTOPINE.     See  OPIUM  ALKALOIDS,  p.  360. 
PSEUDACONITINE.     See  ACONITE  ALKALOIDS,  p.  19. 
PSEUDOMORPHINE.     See  p.  359. 

PTOMAINES.  Cadaveric  Alkaloids.  Ptomaine. — Alka- 
loid-like bodies  formed  in  the  putrefactive  decomposition  of 
animal  tissues.  The  formation  may  commence  shortly  after 
death.  It  may  be  caused  or  promoted  by  digestion  with  acids 
(COPPOLA,  1885),  especially  when  the  mixtures  are  acidulated 
with  sulphuric  acid.  BRIEGER  (1885)  enumerates  the  following 
products  of  the  putrefaction  of  the  human  body : 


PTOMAINES.  427 

Choline,  C5H15NOo. 
Eeuridine,  CgjL^No. 

Cadaverine,  C5H16N2,  boiling  at  115°-120°  C.,  with  water 

at  100°  C. 

Putrescine,  C4H12N2 ,  boiling  at  about  135°  C. 
Saprine,  C5H16IS2. 
Trimethylamine,  C3H9N. 
Mydalein. 
A  ptomaine  boiling  at  284°  C. 

Of  the  above,  only  Choline  is  poisonous. 
From  putrefactive  albumen  and  gelatine  Brieger  (1885)  had 
obtained : 

Neurine,  C5H13NO. 
•  ../    Muscarine,  C5H15NO3. 

An  ethylenediamine,  C2H4(H2N)2. 

Neuridine,  C5H14K2. 

Gadinine,  C7H17JtfO2. 

Triethylamine,  dimethylamine,  and  trimethylamine. 

Of  these  the  first  three  named  are  extremely  poisonous.  The 
greater  number  of  cadaveric  ptomaines  are  non-poisonous. 

Concerning  their  chemical  constitution,  Brieger  (1885)  calls 
attention  to  the  fact  that  most  of  the  characteristic  ptomaines  are 
diamines ;  that  they  are  chemically  more  simple  in  composition 
than  are  the  vegetable  alkaloids ;  that  many  of  the  ptomaines  are 
derivatives  of  hydrocarbons  of  the  ethylene  series,  and  are  in 
distinction  from  true  alkaloids  representing  the  pyridine  group. 

Ptomaines  are  for  the  most  part  obtained  from  tissues  in  the 
operations  of  separation  by  the  immiscible  solvents.  In  evapo- 
rations they  are  liable,  in  part,  to  be  vaporized.  They  are  easily 
decomposed  and  are  affected  by  atmospheric  oxidation.  They 
respond  to  the  greater  number  of  the  general  reagents  for  preci- 
pitation of  alkaloids. 

Cadaverine  hydrochloride,  C5H16N2.2HC],  gives  reactions  as 
follows  (BRIEGER,  1885):  With  phosphomolybdic  acid,  a  white 
crystalline  precipitate.  With  iodide  of  potassium,  or  with  iodine 
in  iodide  solution,  brown  needles ;  with  potassium  bismuth  iodide, 
reddish  needles ;  with  picric  acid,  yellow  needles ;  with  potas- 
sium chromate  and  concentrated  sulphuric  acid,  a  red-brown  pre- 
cipitate, soon  vanishing.  Free  cadaverine  gives  with  potassium 
mercuric  iodide  a  resinous  precipitate  ;  with  potassium  iodide, 
a  brown  precipitate  ;  with  tannic  acid,  a  white  precipitate.  Free 
or  in  salt  it  promptly  reduces  a  mixture  of  ferric  chloride  and 
potassium  ferricyanide,  giving  a  blue  color. 


428  PTOMAINES. 

Putrescine  hydrocliloride,  C4H12N2 .  2HC1,  with  phosphomo- 
lybdic  acid  gives  a  yellow  precipitate ;  with  potassium  mercuric 
iodide,  an  amorphous  precipitate  soon  crystallizing  in  needles ; 
with  iodide  of  potassium,  or  iodine  in  iodide  solution,  a  brown 
crystalline  precipitate. 

Ptomaines  are  mostly  quite  strong  reducing  agents,  and  the 
reaction  of  ptomaine  sulphates  with  ferric  chloride  and  potas- 
sium ferricyanide  (BROUARDEL  and  BOUTMY,  1881)  has  been  an- 
nounced as  characteristic  of  the  animal  alkaloids,  but  this  is  not 
admitted  by  Brieger.  The  latter  states  that  the  reduction  of  the 
ferricyanide  mixture,  with  formation  of  a  blue  color,  is  obtained 
by  cadaverine,  saprine,  mydaleine,  and  some  other  ptomaines, 
not  by  choline,  neuridine,  or  putrescine.  Brieger  further  states 
that  he  has  not  found  a  distinctive  reaction  for  ptomaines.  They 
are  all  precipitated  by  phosphomolybdic  acid,  a  reaction  they 
share  with  ammonia,  as  well  as  with  the  vegetable  alkaloids 
(p.  46).  The  reduction  of  ferricyanide  with  ferric  salt,  forming 
prussian  blue,  is  not  given  promptly  by  many  vegetable  alka- 
loids, but  is  given  at  once  by  morphine  and  veratrine  (Brouardel 
and  Boutmy),  at  once  by  colchicine  (Beckurts,  1882),  and  is 
given  slowly  and  feebly  by  aconitine,  brucine,  conine,  digitaline, 
nicotine,  strychnine,  papaverine,  narceine,  codeine  (Beckurts). 

LETJCOMAINES. — Animal  alkaloids,  more  or  less  septic,  formed 
in  tissues  and  organs  of  the  living  body  : 

Xanthocreatinine,  C5II10N4O.   From  muscular  tissue.     Ee- 

semblee  creatinine. 

Cruscocreatinine,  C5H8N4O . .   Kesembles  creatinine. 
Arnphicreatinine,  C9H19jN7O4. 
Pseudoxanthine,  C4H5N5O .  .  .    Eesembles  xanthine. 

Mytilotoxine,  C6H15NO2 From  mussels  ;  poisonous. 

Betaine,  C5H1:LNO2 From  mussels;  non-poisonous. 

The  first  four  above  given  were  found  by  GAUTIER  (1886) ;  the 
last  two  by  BRIEGER  (1886). 

Neurine  was  obtained  by  MARINO-ZUCO  (1885)  from  fresh 
eggs,  blood,  brains,  liver,  etc.,  by  the  method  of  Stas,  and  more 
abundantly  by  the  method  of  Dragendorff,  and  formed  from  the 
lecithin  of  the  tissues  by  action  of  acids  on  them,  not  formed 
from  the  albuminoids.  These  leucomaines  mask  the  reactions  for 
the  vegetable  alkaloids.  By  repeatedly  extracting  (shaking  out) 
from  alkaline  solution,  with  ether  or  chloroform,  it  was  found 
that  the  neurine  was  left  behind. — From  the  liver  and  spleen,  in 
addition  to  neurine,  a  violet  fluorescent  base  was  obtained. 


PTOMAINES.  429 

Respecting    cheese-poison,   reported    upon    by   VICTOR   C. 

YAUGHAN  in  1884  as  a  poisonous  ptomaine,  and  now  announced 

by  him  as  diazobenzene  salts,  see  Tyrotoxicon,  in  this  work. 

The    literature  of    ptomaines   and   leucomaines   is    mainly 

embraced  in  that  of  physiological  and  pathological  chemistry. 

Among  the  publications  of  interest  in  analytical  chemistry  and 

toxicology,  an  index  is  here  made  of  the  following : 

DUPRE  and  BENCE  JONES,  1866  :  Respecting  a  frail  alkaloid-like 
body  found  in  the  organs  and  liquids  of  the  bodies  of  man 
and  of  animals,  Zeitsch.  Chem.  und  Phar.,  1866 ;  Phar. 
Centralh.,  16 ;  Ber.  d.  chem.  Ges.,  7,  1491. 

SONNENSCHEIN  and  ZULZER,  1869  :  On  bases  obtained  from  mus- 
cular tissue,  Berlin  Jdin.  Wochenschr.,  1869,  123. 

RORSCH  and  FASSBANDER,  1871 :  On  a  body  giving  reactions  for 
alkaloids,  found  in  analyses  of  liver,  etc.,  for  poisons,  Ber. 
d.  chem.  Ges.,  7,  1064. 

SSLMI,  chiefly  about  1878 :  On  toxicology,  1876,  Gazzetta  thim. 
ital.,  4,  1 ;  Jour.  Chem.  Soc.,  27,  607.  On  alkaloids  of  cada- 
veric putrefactions,  1873  to  1880:  Ber.  d.  chem.  Ges.,^ 
142;  8,  1198;  9,  195;  II,  808,  1838;  12,  279;  13,  206. 
"  Sulle  Ptomaine  ad  alkaloidi  cadaverici,"  Bologna,  1878. 
On  alkaloids  in  the  cadaver,  1879,  Gazzetta  chim.  ital.,  9, 
35 ;  Jour.  Chem.  Soc.,  36,  734.  On  a  poisonous  alkaloid 
from  a  cadaver  containing  arsenic,  1 879 :  Gazzetta  chim. 
ital.,  9,  33;  Jour.  Chem.  Soc.,  36,  734.  On  an  alkaloid 
found  in  the  brain  and  liver,  and  in  the  wild  poppy,  1876, 
Gazzetta  chim.  ital.,  5,  398 ;  Jour.  Chem.  Soc.,  29,  938.  On 
pathological  bases,  1881,  Gazzetta  chim.  ital.,  1881,  546; 
Jour.  Chem.  Soc.,  42,  741. 

TH.  HUSEMANN,  1881 :  The  ptomaines  in  toxicology,  Archiv 
der  Phar.  [3]  16,  415 ;  Am.  Jour.  Phar.,  54,  152. 

H.  BECKURTS,  1882  :  Distinctions  between  cadaver  and  plant  al- 
kaloids, Archiv  der  Phar.  [3]  17,  104  ;  Am.  Jour.  Phar., 
54,  221.  Zeitsch.  anal.  Chem.,  24,  485. 

BROUARDEL  and  BOUTMY,  1881:  Distinctive  reactions  of  pto- 
maines, Ber.  d.  chem.  Ges.,  14,  1293;  Compt.  rend.,  92, 
1056. 

MARINO-ZUCO,  1884 :  Ptomaines  in  toxicology,  Gazzetta  chim. 
ital.,  13,  431,  441 ;  Jour.  Chem.  Soc.,  46,  342,  343. 

ARNOLD,  1884 :  Ptomaines  in  toxicology,  Archiv  der  Phar.  [3] 
21,  435  ;  Jour.  Chem.  Soc.,  46,  469. 

GARNIER,  1883 :  Ptomaines  in  toxicology,  Jour,  de  Phar.,  7, 
377  ;  Am.  Jour.  Phar.,  55,  404. 

L.  BRIEGER,  Berlin,  1884-87 :  "  Ueber  Ptomaine,"  Berlin,  1885. 


430  PYROGALLOL. 


Zeitsch.  physiolog.  Chem.,  3,  135 ;  9,  1.  "  Weitere  Unter- 
suchungen  uber  Ptomaine,"  Berlin,  1885-86.  Ber.  d.  chem. 
Ges.,  17,  274:1 ;  Zeitsch.  anal.  Chem.,  24,  4:84:.  A  new  pto- 
maine producing  tetanus,  Ber.  d.  chem.  Ges.,  19,  3119 ; 
Jour.  Chem.  Soc.,  52,  284. 

MAAS  and  others,  1884:  Ptomaines  in  boiled  meat,  Chem.  Cent., 
1884,  975 ;  Jour.  Chem.  Soc.,  48,  676. 

Y.  C.  YAUGHAN,  1884-85  :  A  ptomaine  from  poisonous  cheese, 
Zeitsch.  physiolog.  Chem.,  10,  146;  Jour.  Chem.  Soc.,  50, 
373.  Michigan  State  Board  of  Health  Reports.  (See  "  Ty- 
rotoxicon,"  in  this  work.) 

COPPOLI,  1885  :  Ptomaines  formed  by  processes  of  analysis  of 
tissues  for  poisons,  Gazzetta  chim.  ital.,  14,  124,  571;  Jour. 
Chem.  Soc.,  48,  278,  913. 

GAUTIER,  1885-86 :  Leucornaines,  Bull.  Soc.  Chim.,  43,  158  ; 
Jour.  Chem.  Soc.,  48,  676.  On  alkaloids  of  bacterial  origin, 
'etc.,  Paris,  1886.  Ptomaines  and  Leucomaines,  1886,  Jour. 
Phar.  [5]  13,  354;  Jour.  Chem.  Soc.,  50,  634. 

LADENBURG,  1885:  Ber.  d.  chem.  Ges.,  18,  2956,  3100. 

OLIVERI,  18&6  :  Supposed  ptomaines  of  cholera,  Gazzetta  chim* 
ital.,  16,  256 ;  Jour.  Chem.  Soc.,  50,  1049. 

PURPURINE.     See  COLORING  MATERIALS,  p.  190. 
PURPUROGALLIN.     See  p.  431. 

PYROGALLOL.  C6H6O3  =  C6H3(OH)3  =  126.  Pyro- 
gallic  Acid. — Manufactured  from  gallic  acid  or  from  gallotan- 
nin  by  sublimation.  One  part  of  gallic  acid  with  two  parts  of 
powdered  pumice  stone  may  be  heated  to  2100-220°C.  in  a 
stream  of  carbon  dioxide.  To  obtain  colorless,  sublimed  in  a 
vacuum  at  210°  C.  Used  as  a  reducing  agent  in  photography  ; 
also  to  a  limited  extent  in  hair  dyes,  either  by  itself  or  to  reduce 
silver. 

Pyrogallol  is  identified  by  its  reactions  with  alkalies  and  iron 
salts,  and  its  formation  of  purpurogallin.  It  is  separated  from 
tannic  acid  by  its  not  precipitating  with  gelatin.  It  may  be 
estimated  in  a  lead  compound. 

Pyrogallol  crystallizes  in  lustrous  plates  or  needles  of  white 
or  yellowish- white  color,  a  very  bitter  taste,  without  odor,  and  a 
neutral  or  very  feebly  acidulous  reaction.  It  gives  a  brown  color 
to  the  skin.  The  crystals  are  changeless  in  dry,  pure  air,  dark- 
ening in  ammoniacal  air.  It  melts  at  115°  C.,  boils  at  210°  C., 


PYROGALLOL.  431 

and  at  about  250°  C.  blackens  with  production  of  metagallic  acid. 
(See  Gallic  Acid,  p.  321.)  It  dissolves  in  three  parts  of  water, 
freely  in  alcohol  and  in  ether,  not  in  absolute  chloroform.  The 
watery  solution  darkens  on  standing,  sooner  if  heated,  quickly 
coloring  by  addition  of  alkalies,  with  formation  of  alkali  carbonate 
and  acetate,  absorption  of  oxygen  taking  place  to  an  extent  pro- 
portional to  the  coloration,  which  is  destroyed  by  oxalic  acid. 
The  alkalies  cause  reddish-yellow  to  red -brown  tints ;  lirne  solu- 
tion, a  violet  to  purple  color ;  all  becoming  gradually  brown  to 
black. 

Ferroso  ferric  salts,  slightly  oxidized  ferrous  salts  the  better, 
give  a  clear  blue  color.  If  there  be  much  ferric  salt  the  color 
soon  turns  to  red,  and  with  ferric  salt  alone  the  color  is  reddish 
at  first.  If  the  very  dilute  solution  of  ferric  salt  and  pyrogallol 
be  gradually  treated  with  ammonia,  the  color  changes  first  from 
red  to  blue,  and  then  back  to  bright  red.  (The  reaction  is  like 
that  of  purpurogallin,  given  below.)  By  gradually  adding  then 
acetic  acid  or  other  organic  acid,  the  blue  is  first  restored,  then  a 
red  color  again  appears.  Hydrochloric  acid  and  most  inorganic 
acids  give  at  once  a  red  color.  The  blue  color  is  produced  by 
bicarbonates  as  well  as  by  ammonia,1  also  by  free  alkaloids 
(SCHLAGDENHAUFFEN). — In  presence  of  gum  arabic,  blood,  saliva, 
and  various  other  organic  substances,  pyrogallol,  in  solution, 
exposed  to  the  air,  gradually  forms  PURPUROGALLIN,  C20H16O9 
(STRUVE).  The  same  product  is  obtained  at  once  by  adding  a 
strong  solution  of  permanganate  acidulated  with  sulphuric  acid. 
Purpurogallin  has  a  red  color  of  much  intensity,  imparted  to 
solutions,  from  which  it  crystallizes  in  yellow  to  red  needles,  and 
by  sublimation  is  obtained  in  garnet-red  crystals.  It  is  sparingly 
soluble  in  water,  and  its  solution,  with  an  alkali,  gives  a  transient 
blue  color  of  great  intensity.2 

Pyrogallol  is  a  most  forcible  reducing  agent,  promptly  re- 
ducing salts  of  silver  and  mercury,  and  Fehling's  solution,  and 
reducing  ferric  salts  in  the  iron  reactions  above  given.  It  is 

'JACQUEMIN,  1874  and  1876-77:  Ann.  Chim.  Phys.  [4]  30,  566;  Jour. 
Client,.  Soc.,  27,  1016;  Jour.  Chem.  Soc.,  31,  340.  A  very  dilute  solution  of 
ferric  chloride  and  pyrogallol  is  used  as  an  indicator,  more  delicate  than  litmus, 
for  the  estimation  of  ammonia  or  of  bicarbonates  (as  in  mineral  waters).  The 
solution  is  made  of  equal  volumes  of  a  solution  of  5  grams  pyrogallol  to  the 
liter,  and  a  solution  of  2  grains  ferric  chloride  to  the  liter.  It  deposits  purpu- 
rogallin, and  needs  to  be  filtered  from  time  to  time.  Of  the  solution  10  c.c.  are 
added  to  250  c.c.  of  water  for  alkalimetry. 

4  As  to  ethers  of  pyrogallol,  and  their  color  products,  see  "  Watts's  Diet.," 
viii.  1710.  Pyrogalloquinone,  ibid.  1713.  Reaction  with  mercuric  chloride 
and  alkaloids,  ibid.  1709. 


432  RACE  MIC  ACID. 

attacked  by  nitric  acid,  with  red  products.  Its  dry  mixtures 
with  many  oxidizing  agents  are  explosive.  In  aqueous  solution, 
with  alkali,  it  removes  nearly  all  the  oxygen  from  a  contined 
portion  of  air. 

A  gravimetric  estimation  may  be  made  by  adding  to  an 
alcoholic  solution  of  pyrogallol  an  alcoholic  solution  of  lead 
acetate,  faintly  acidulated  with  acetic  acid,  quickly  washing  the 
precipitate  with  alcohol,  drying  on  a  water-bath,  and  weighing. 
rb(C6H5O3)2  :  2C6H6O3  ::  457  :  252  ::  1  :  0.5514. 

QUINAMINE.     See  CINCHONA  ALKALOIDS,  p.  92. 

QUINICINE.     See  p.  94. 

QUINIDINE.     See  p.  154. 

QUININE.     See  p.  125. 

QUI.NOIDINE.     See  p.  94. 

QUINOLINE.     See  p.  165. 

QUINOLINE  RED.     See  COLORING  MATERIALS,  p.  182. 

RACEMIC  ACID.  H2C4H4Oe  =  150.  Paratartaric  Acid. 
Traubensaure.  Separable  Inactive  Tartaric  Acid. — An  isomer 
of  tartaric  acid,  found  in  some  varieties  of  grapes,  and  differing 
from  dextrotartaric  acid  in  the  form  of  crystallization,  in  optical 
powers,  and  in  its  solubilities  as  free  acid  and  as  calcium  salt. 
It  crystallizes  in  the  triclinic  system,  with  one  molecule  of  water, 
becoming  anhydrous  at  100°  C.  It  is  soluble  in  about  5  parts  of 
cold  water  and  in  48  parts  alcohol  of  0.809  specific  gravity.  Its 
solution  is  optically  inactive,  not  rotating  the  plane  of  polarized 
light,  but  it  is  separable  into  dextrotartaric  and  levotartaric  acids, 
as  follows :  When  the  racemates  of  two  bases,  as  sodium  and 
ammonium,  in  molecular  proportions,  are  crystallized  from  solu- 
tion together,  crystals  of  a  double  salt,  as  NaNH4C4II4O6,  are 
obtained,  and  these  crystals,  rectangular  prisms,  have  certain 
hemihedral  faces,  and  are  divided  into  pairs,  right  and  left,  by 
the  position  of  the  hemihedral  faces.  The  one  crystal  of  a  pair 
coincides  with  the  reflection  of  the  other  from  a  mirror.  When 
the  two  kinds  of  crystals  are  separated  by  hand-picking,  the  one 
kind  is  found  to  be  the  salt  of  dextrotartaric  acid,  identical  with 
ordinary  tartaric  acid,  while  the  other  kind  is  a  salt  of  another 


SALICYLIC  ACID.  433 

tartaric  acid  isomer,  whose  solution  rotates  the  light  plane  to  the 
left,  and  is  termed  Levotartaric  Acid,  or  anti tartaric  acid. — 
Racemic  acid,  free,  forms  a  precipitate  with  calcium  sulphate 
solution  on  standing,  and  a  precipitate  with  calcium  chloride 
solution  quite  readily ;  also,  the  calcium  precipitate,  dissolved 
by  hydrochloric  acid,  is  precipitated  again  by  ammonia  (distinc- 
tions from  dextrotartaric  acid). 

RHOEADINE.     See  OPIUM  ALKALOIDS,  p.  360. 

RICINOLEIC  ACID.  See  FATS  AND  OILS,  pp.  246,  248, 
289. 

RESIN,  COMMON,  SEPARATION  OF.     See  FATS  AND 

OILS,  p.  278. 

ROSIN  OILS.     See  p.  280. 

SAFFLOWER  RED.     See  COLORING  MATERIALS,  p.  191. 

SAFFRANINS.     See  p.  183. 

SALICYLIC  ACID.— Salicylsaure.  Acide  Salicylique. 
O7H6O3  =  138  (monobasic  and  with  alkalies  feebly  dibasic).  In 
structure,  C6H4.CO2H.OH,  in  which  CO2H  :  OH  =  I  :  2,  or- 
tho-hydroxybenzoic  acid. — There  is  but  one  salicylic  acid,  but  it 
is  one  of  three  isorneric  hydroxybenzoic  acids  (or  phenol- car- 
boxylic  acids),  namely,  the  ortho,  meta,  and  para  compounds, 
with  the  respective  positions  of  1:2,  1:3,  and  1  :  4,  for 
C02H  :  OH. 

Sources. — Free  salicylic  acid  occurs  very  sparingly  in  nature, 
having  been  found  in  the  flowers  of  Spiraea  ulmaria,  in  Viola 
tricolor  and  other  species  of  viola,  and  in  the  Gloriosa  superba 
of  the  East  Indies.  The  ethereal  salt,  salicylate  of  methyl, 
C6H4.CO2(CH3).OH,  is  known  as  "wintergreen  oil."  Methyl 
salicylate  forms  the  larger  part  (over  99  per  cent.,  PETTIGREW, 
1884;  90  per  cent.,  CAHOURS,  1843)  of  the  oil  of  gaultheria,  IT. 
S.  Ph.  ;  according  to  Pettigrew  the  whole  of  the  "  oil  of  birch," 
from  Betula  lenta  bark,  commonly  sold  as  "  wintergreen  oil "  ;  and 
nearly  or  quite  the  whole  of  the  oil  of  Andromeda  Leschenaultii, 
of  abundant  growth  in  Hindostan,  and  the  volatile,  oil  of  Mono- 
tropa  Hypopitys  of  northern  Europe.  It  is  also  found  in  the 
oils  of  several  species  of  Gaultheria  and  in  oil  of  Poly  gala  pauci- 
flora  ;  sometimes  in  oil  of  cloves,  and  in  oil  from  buchu  leaves. 


434 


SALICYLIC  ACID. 


Salicylic  acid  may  be  prepared  from  methyl  salicylate  by  boiling 
with  potassium  hydrate  solution  until  the  oil  is  dissolved,  and 
as  long  as  methyl  alcohol  is  given  off,  and  then  acidulating  with 
hydrochloric  acid,  when  the  salicylic  acid  precipitates.  Since 
1874  salicylic  acid  has  been  extensively  manufactured  from 
carbolic  acid  by  Kolbe's  method.1  Dry  sodium  phenol, 
C6H5ONa,  is  treated  with  dry  CO2 ,  at  a  temperature  increased 
to  180°  C.  and  finally  to  about  225°  C.,  whereby  disodium  sali- 
cylate, C6H4.CO?Na.O]S"a,  is  formed  in  the  retort,  and  half 
the  phenol  taken  is  distilled  over.  Small  portions  of  para-hy- 
droxybenzoic acid  and  traces  of  a  phenol-dicarboxylic  acid  are 
formed  (OsT,  18T9).  If  potash  be  used  instead  of  soda  the  pro 
duct  is  the  para-hydroxybenzoic  acid.  But  impurities  of  greater 
proportion  in  salicylic  acid  made  from  -carbolic  acid  probably 
result  from  the  impurities  in  the  latter,  namely,  from  the  cresols 
homologous  with  phenol  (the  "  cresylic  acid  "  )  present  in  carbo- 
lic acid  (see  Phenol).  Each  of  the  three  cresols,  C7H8O,  treated 
with  sodium  and  carbon  dioxide,  forms  a  cresotic  acid,  C8H8O3. 
The  cresotic  acids  so  formed  are  sometimes  termed  the  liomo- 
salicylic  acids,  and  are  direct  homologues  of  salicylic  acid,  hav- 
ing the  rational  formula,  C6H3(CH3) .  CO2H .  OH,  with  the  posi- 
tions CO2H  :  OH  :  CH3  =  respectively  1  :  2  :  3,  and  1  :  2  :  4, 
and  1:2:  5.2 

1  Concerning  recent  manufacture  of  salicylic  acid  through  formation  of 
diphenyl  carbonate,  at  the  works  of  Aktien  (late  Schering)  in  Berlin,  see  Jahr. 
chem.   'Tech.,   1884,   504;  HENTSCHELL,  Jour,  prakt.  Chem.,  27,  159,  and  Jour. 
Soc.  Chem.  Ltd.,  3,  115,  646. 

2  These  three  cresotic  acids  are  but  three  isomers  among  ten  known  isome- 
ric  hydroxytoluic   acids  (or     cresol-carboxylic  acids)  obtained    from    various 
sources.     Beilxteiiis  Organisch.   Chemie.   1883,  p.  1457.     In  part  in  "  Watts's 
Diet.,"  viii.  2«'23.    Concerning  certain  of  these  acids  and  xylene  products,  Am. 
Chem.  Jour..  3,  424;  4,  186.    Concerning  three  hydroxyxylenic  acids,  GUNTER, 
1884:  Ber.  d.  chem.   Ges.,   17,  1608;  Jour.    Chem.  Soc.',  1884,  Abs..  1347.     It 
will  be  observed  that  the  occurrence  of  homologues  in  salicylic  acid  from  coal- 
tar  corresponds  to  the  existence   of  homologues  in  carbolic  acid  and  in  the 
benzoles,  as  follows: 


1.  Benzene C8H6. 

Toluene C7H8. 

Xylenes C8H]  0 , 


2.  Phenol C6H60. 

Cresols  (see  p.  394) C7H80. 

Xylenols C8H100 . 


3.  Benzoic  acid C7H602 . 

Toluic  acids C8H802 . 

Xylenic  acids CgHj002 . 


4.  Salicylic  and  two  other 

hydroxybenzoic  acids  .  C7H603 . 

Cresotic  and  other  hy- 
droxytoluic acids C8H803. 

Hydroxyxylenic  acids. . .  C9Hi003. 


SALICYLIC  ACID.  435 

The  question  of  the  occurrence  of  the  homologues  and  iso- 
mers  of  true  salicylic  acid,  in  the  article  made  from  carbolic 
acid,  is  further  treated  under  Impurities  (g).  At  all  events,  the 
crude  sodium  salicylate  of  Kolbe's  process  is  acidulated  with  hy- 
drochloric acid,  and  the  resulting  crude  salicylic  acid  is  purified 
in  various  ways,  by  crystallizations  from  dilute  alcohol  or  hot 
water,  by  dialysis  of  the  sodium  salt,  and  by  filtration  through 
purified  animal  charcoal.  Dr.  Squibb  (1877)  employed  sublima- 
tion of  the  acid  by  heat  from  steam.  For  some  years  the  "  natu- 
ral salicylic  acid  "  has  been  manufactured  from  "  wintergreen 
oil"  in  this  country,  for  medicinal  purposes, with  claims  for  supe- 
rior purity. — The  essential  oil  of  the  flowers  of  Spiraea  ulmaria, 
Salicylol)  is  the  aldehyd  of  salicylic  acid.  The  glucoside  Sali- 
cin,  the  active  principle  of  Salix,  readily  liberates  the  correspond- 
ing alcohol,  saligenin.  From  all  these  substances,  from  indigo, 
and  from  coumaric  acid,  salicylic  acid  can  be  obtained  by  heat- 
ing with  potassium  hydrate  under  suitable  conditions,  and  by 
other  chemical  treatment. 

SALICYLIC  ACID  is  identified  by  its  crystalline  form  and  physi- 
cal deportment  (#),  its  reaction  with  ferric  salt  and  with  nitric 
acid,  and  the  odor  of  its  methyl  ester  (d).  From  Benzoic  acid  it 
is  distinguished  by  the  odor  of  the  respective  products  with  so- 
dium amalgam  in  presence  of  water,  and  with  lime  by  heating 
when  dry  (d) ;  from  Cinnamic  acid  by  the  permanganate  oxida- 
tion of  the  latter  to  benzoic  aldehyde.  It  can  be  separated  and 
its  valuation  secured  (e)  by  distillation  from  its  salts  (1),  or  of  the 
free  acid  (3) ;  by  solvents  not  miscible  with  water  (2) ;  by  dialy- 
sis (4) ;  and  in  special  methods  from  Wine  and  Beer  (p.  440), 
Canned  Fruits,  Milk  (p.  440),  and  the  Urine  (p.  441).  Quantita- 
tively it  is  estimated  (f)  by  the  colorometric  method,  or  weighed 
as  free  acid.  It  is  examined  respecting  impurities  and  require- 
ments of  quality  (g)  with  regard  to  its  modes  of  manufacture 
(p.  434)  and  its  chemical  isomers  (p.  443),  by  application  of  re- 
cognized special  tests  (p.  444).  For  Salicyluric  Acid  see  p.  445; 
Salicylate  of  Sodium,  p.  445 ;  other  salicylates,  p.  437. 

a. — Salicylic  acid  is  furnished,  according  to  its  grade,  in  fine, 
needle-shaped  crystals,  or  in  a  loose  or  granular  powder,  obscure- 
ly crystalline  or  nearly  amorphous.  White  when  pure,  it  is  fre- 
quently blemished  with  a  yellowish,  or  pinkish,  or  brownish 
tinge.  The  dialyzed  acid  is  said  to  keep  perfectly  white.  The 
"  recrystallized  "  acid  is  a  good  pharmacopoeial  brand ;  the  "  pre- 
cipitated "  acid  is  of  a  lower  grade  ;  the  "  sublimed ''  acid  is  said 


436  SALICYLIC  ACID. 

to  acquire  color  and  carbolic  odor.  The  crystals  are  monoclinic 
(MARIGNAC,  1855).  From  moderately  warm  aqueous  solution  it 
is  obtained  in  four-sided  prisms,  from  hot  aqueous  solution  in 
needles,  from  alcoholic  solution  by  spontaneous  evaporation  in 
large  four-sided  columns,  from  a  drop  of  ether-solution  evapo- 
rated on  a  glass  slide  in  star  form  or  feathery  groups  of  radiate 
needles  requiring  to  be  magnified  50  to  100  diameters  (HAGEE). — 
Sp.  gr.  1.483  at  medium  temp.,  taking  water  at  i°  C.  as  1 
(SCHROEDER,  1879).  Permanent  in  the  air.  Melts  at  156°  C. 
(312°  F.)  (HiiBNER,  1872 ;  KOHLEK,  1879).  Sublimes  unaltered 
by  heat  from  steam  at  60  to  80  Ibs.  pressure,  not  above  145°  C. 
(293°  F.),  the  product  having  no  carbolic  odor  (SQUIBB,  1883). 
Suddenly  heated,  at  220°-230°  C.  (428°-446°  F.),  it  is  resolved 
into  phenol  and  carbon  dioxide,  leaving  no  residue,  and  when 
sublimed  without  care  the  sublimate  is  contaminated  with  phe- 
nol and  gives  a  carbolic  odor  In  boiling  its  aqueous  solution  it 
vaporizes  unaltered  with  the  steam.  Heated  with  concentrated 
hydrochloric  or  dilute  sulphuric  acid,  under  pressure,  at  140°- 
150°  C.,  it  is  dissociated  into  phenol  and  carbon  dioxide.  Alkali 
salicylates  oxidize  readily. 

J. — Pure  salicylic  acid  is  odorless  and  has  a  sweetish,  acidu- 
lous, acrid  taste.  The  acid  of  commerce  sometimes  has  the  odor 
of  phenol  or  of  cinnamic  acid.  Salicylic  acid  is  not  caustic,  but 
is  somewhat  irritant  to  mucous  surfaces,  the  more  so  by  inhala- 
tion in  dust.  It  is  medicinal  in  ordinary  doses  of  10  to  60  grains. 
If  more  than  150  grains  be  given  within  twe,nty-four  hours  some 
disturbance  usually  follows.  The  alkali  salicylates  have  the 
effect  of  the  acid,  as  does  also  methyl  salicylate  (Gaultheria  oil) 
(H.  C.  WOOD  and  H.,  1886).  In  hypodermic  injections  about 
0.2  per  cent.,  or  the  strength  of  a  cold  saturated  aqueous  solution 
of  the  acid,  is  employed.  For  external  application  1  to  10  per 
cent,  solutions  are  used.  Salicylic  acid  is  removed  from  the 
system  with  moderate  rapidity,  most  largely  by  the  urine,  in  part 
by  the  bile,  and  in  traces  by  the  saliva.  Gaultheria  oil  becomes 
free  salicylic  acid  in  the  living  body  (Wooo,  1886 :  Ther.  Ga- 
zette, 10,  73).  In  the  urine  salicylic  acid  is  excreted  as  salicyluric 
acid,  with  unchanged  salicylic  acid.  Other  reported  excretory 
products  are  phenol,  salicin,  and  indican. — Salicylic  acid,  in 
proportion  of  about  0.1  per  cent.  (}  grain  to  the  fluid- ounce), 
preserves  ordinary  vegetable  infusions.  For  fruit  juices,  cider, 
etc.,  0.05  to  0.3  per  cent,  is  requisite,  but  0.01  to  0.02  per  cent, 
exerts  a  degree  of  conserving  power.  To  preserve  hypodermic 
and  alkaloidal  solutions  Dr.  Squibb  uses  the  full  or  half  strength 


SALICYLIC  ACID.  437 

of  a  cold  water  saturated  solution  (0.2  or  0.3$). *  As  an  antizymotic, 
or  antiseptic,  the  salicylates  have  much  less  power  than  the  free 
acid,  and  a  sufficient  quantity  of  bisulphate  of  potassium  may  be 
added  to  complex  liquids,  with  salicylic  acid,  to  prevent  its  com- 
bination with  the  bases  of  acetates,  etc.  The  use  of  salicylic  acid 
in  foods  has  been  forbidden  in  some  countries. 

G. — Salicylic  acid  is  sparingly  soluble  in  water:  at  15° C. 
(59°  F.)  it  requires  444  parts ;  at  20°  C.  (68°  F.).  370  parts ;  at 
30°  C.  (86°  F.),  256  parts;  at  100° C.  (212°  F.),  13  parts  (Boun- 
GOIN,  1879).  Heated  with  water  under  pressure,  the  acid  dis- 
solves water  and  liquelies  (ALEXEJEFF,  1883).  In  alcohol  of  90$  it 
dissolves  in  2.4  parts  at  15°  C.  (59°  F.) ;  in  absolute  alcohol,  in  2 
parts  at  15°  C.  It  dissolves,  at  15°  C.  (59°  F. ),  in  2  parts  of  ether, 
in  3.5  parts  of  amyl  alcohol,  freely  in  methyl  alcohol,  in  80  parts 
of  benzene,  in  80  parts  of  chloroform,  in  60  parts  of  glycerin,  and 
in  about  60  parts  of  ordinary  fixed  oils.  It  dissolves  in  carbon 
disulphide  and  in  volatile  oils.2 

Salicylic  acid  has  an  acid  reaction  ;  it  causes  effervescence 
from  carbonates ;  it  forms  moderately  stable  monobasic  or  normal 
salts  (as  CgE^.COjjNa. OH),  those  of  the  alkali  metals  being 
neutral  to  litmus  (when  pure),  and  instable  dibasic  salts  (as 
CgH^.COgNa.OJSra)  of  alkaline  reaction.  For  conserving 
certain  alkaloids  the  salicylate  is  a  very  favorable  salt.  Of 
the  normal  salts,  those  of  alkalies,  calcium,  barium,  magnesium, 
zinc,  and  copper  dissolve  in  water,  the  lead  salt  in  hot  water,  but 
the  silver  salt  does  not  readily  dissolve.  The  basic  salts  of  non- 
alkali  metals  are  not  soluble  in  water.  Salicylate  of  quinine, 
C20H24]Sr2O2.C7H6O34(H2O),  is  neutral  and  soluble  in  900 parts 
of  cold  water  or  20  parts  of  alcohol ;  salicylate  of  atropine  is 
neutral  and  very  soluble  in  water. — With  the  alkali  salts  of  the 
weaker  acids  salicylic  acid  dissolves  freely  in  water,  making 
comparatively  concentrated  solutions,  which,  however,  are  really 
solutions  of  salicylates.  Borax,  acetate  of  potassium,  and  acetate 
of  ammonium  are  used,  also  alkali  phosphates  and  citrates,  with 
water,  as  solvents.  With  borax  a  crystallizable  union  is  obtained, 
NaC7H5O3  +  C7H5(BO)O3,  of  acid  reaction.  With  half  its 

'ROBINET  and  PELLET,  1882:  Compt.  rend.,  94,  1322;  Jour.  Chem.  Soc., 
42,  1010.  BERSCH,  1882:  "  Biedermann's  Centralblatt,"  p.  340;  Jour.  Chem. 
Soc.,  42,  1010.  HEINZELMANN,  1884:  "Biedermann's  Centralblatt,"  p.  503; 
Jour.  Chem.  Soc.,  46,  764.  "  Hager's  Phar.  Praxis,"  Erganzungsband,  43. 
SQUIBB'S  Ephcmeris,  1882-85:  i,  414;  2,  833. 

2LANGBECK  (1884)  reports  widely  varying  solubilities  of  salicylic  acid  in 
different  essential  oils,  and  uses  this  difference  to  distinguish  volatile  oils  from 
each  other:  Repert.  anal.  Chem.,  12,  177;  Jour.  Soc.  Chem.  Ind.,  3,  547. 


438  SALICYLIC  ACID. 

weight  of  borax,  and  2J  times  its  weight  of  glycerin,  a  25  per 
cent,  solution  of  salicylic  acid  may  be  obtained.  The  combina- 
tion with  boric  acid,  borosalicylic  acid,  C7H5(BO)O3.C7H6O3, 
is  soluble  in  200  parts  of  cold  water  (HAGER).  Glycerin  sali- 
cylate  can  be  formed  (GorriG,  1877). — Solutions  of  salicylic  acid 
and  its  salts  are  not  easily  preserved,  and  acquire  color  by 
standing. 

d — The  stronger  acids  precipitate  salicylic  acid  from  solu- 
tions of  its  salts  in  less  than  200  to  400  parts  of  water.  Silver 
nitrate  solution,  with  solutions  of  saiicylates,  not  with  solution 
of  salicylic  acid,  forms  a  white  precipitate  of  silver  salicylate, 
C7H5AgO3,  dissolved  by  boiling  water,  also  by  nitric  acid  and 
alcohol.  Ferric  chloride  solution,  with  solutions  of  salicylic 
acid  or  its  salts,  gives  (according  to  dilution)  a  violet-blue  to 
violet-red  color  of  great  intensity.  The  alcoholic  solution  of 
free  acid  is  most  favorable.  A  little  less  delicate  than  the  sul- 
phocyanide  reaction  (E.  F.  SMITH,  1880),  it  reveals  salicylic  acid 
diluted  to  100000  parts  (ALMEN,  1878).  The  reaction  is  pre- 
vented by  alkalies,  and  hindered  by  alkali  acetates,  phosphates, 
borates,  potassium  iodide,  and  by  oxalic,  tartaric,  citric,  phos- 
phoric, and  arsenic  acids,  not  by  dilute  acetic,  boracic,  sulphuric, 
or  nitric  acid,  nor  by  glycerin,  alcohol,  ether,  common  salt,  or 
nitre  (HAGER,  1880).  The  ferric  violet  reaction  is  given  by  sali- 
cyluric  acid  and  oil  of  spiraea,  not  by  para  or  by  rrieta  oxyben- 
zoic  acid;  and  red  to  blue  ferric  colors  are  given  by  brorno 
and  nitro  salicylic  acids  and  salicyl-sulphonic  acid.  (See  Car- 
bolic acid,  ferric  reaction.) — Bromine  water  gives  a  crystalline 
precipitate,  C7H4Br2O3,  very  ^slightly  soluble  in  water,  freely 
soluble  in  alcohol.  Solution  in  40000  parts  of  water  gives 
crystals  seen  under  the  microscope  (ALMEN,  1878). — Nitric  acid, 
if  concentrated,  in  the  cold,  and  if  dilute,  by  warming,  forms 
nitro-salicylic  acids,  then  by  more  intense  action  forms  nitro- 
phenic  (picric)  acids,  the  latter  recognized  by  its  intense  red- 
brown  color.  The  reaction  is  most  promptly  obtained  by  Mil- 
Ion's  reagent,  fuming  acid  mercuric  nitrate,  and  gives  color  in 
dilution  with  1000000  parts  of  water  (ALMEN,  1878).— Copper 
sulphate,  with  neutral  solution  of  salicylate,  gives  a  green  color. 
— Glucose  with  from  two  to  three  times  its  weight  of  salicylic 
acid,  the  mixture  warmed  with  excess  of  sulphuric  acid  (concen- 
trated), gives  a  fine  blood-red  color.  Nearly  the  same  color  is 
given  by  benzoic  acid  in  this  test ;  a  brown  to  blood-red  color  by 
hippuric  acid  (PmpsoN,  1873). — Sodium  amalgam,  warmed  in 
a  slightly  acidulated  solution,  gradually  reduces  salicylic  acid  to 


SALICYLIC  ACID.  439 

its  aldehyde,  oil  of  spiraea,  C6H4.COH.OH,  recognized  by  its 
odor  (compare  with  Benzoic  acid). — A  mixture  of  equal  volumes 
of  sulphuric  acid  and  methyl  alcohol,  distilled  from  a  small 
portion  of  residue  containing  salicylic  acid  or  salicylate,  yields 
a  distillate  odorous  of  wintergreen  oil,  methyl  salicylate, 
CH3.C7H5O3.  Ethyl  salicylate,  formed  in  a  corresponding 
way,  has  a  similar  odor. — Heated  with  lime,  salicylic  acid  gives 
the  odor  of  phenol,  obtained  also  by  heating  salicylates  alone  (see 
a).  Salicylic  acid  reduces  permanganate  of  potassium  solution, 
but  does  not  reduce  potassium  cupric  tartrate. — Sulphuric  acid, 
not  diluted,  in  contact  with  salicylic  acid  at  a  gentle  heat,  pro- 
duces salicyl-sulphonic  «<?^(REMSEN,  1875), 

CeH3(SO8H) .  OH .  CO3H  =  C7H6SO6 , 

a  quite  stable  acid,  forming  both  monobasic  and  dibasic  metallic 
salts,  all  soluble  in  water,  mostly  insoluble  in  alcohol. 

e. — Separation. — (1)  Evaporation  on  the  common  water-bath 
carries  away  free  salicylic  acid,  and  is  inapplicable  to  its  aqueous 
solutions.  To  prevent  waste  by  evaporation,  either  bicarbonate 
of  sodium  or  ammonia- water  is  added  to  obtain  a  permanent 
neutral  or  very  slightly  alkaline  reaction  during  the  concentra- 
tion. Long  evaporation  now  endangers  loss  by  decomposition. 
If  a  dry  residue  be  desired,  the  choice  of  ammonia  for  saturation 
of  the  acid  has  this  advantage :  if  the  evaporation  be  concluded 
and  the  residue  dried  at  a  gentle  heat,  the  excess  of  ammonia  is 
expelled.  After  acidulating  the  residue  the  salicylic  acid  may 
be  separated  by  suitable  solvents,  or  dissolved  to  estimate  by  the 
colorimetric  method.  —Alcohol,  ether,  chloroform,  benzene,  etc., 
may  be  evaporated  or  distilled  from  salicylic  acid  without  its 
waste. 

(2)  Shaking  with  chloroform,  ether,  amyl  alcohol,  or  benzene  is 
very  generally  employed  to  remove  salicylic  acid  from  watery 
solutions.  If  the  acid  be  not  wholly  free  from  combination  with 
all  bases,  it  must  be  liberated  by  addition  of  sufficient  acid, 
preferably  dilute  sulphuric  or  phosphoric.  The  solvent  must  be 
applied,  in  successive  portions,  as  long  as  a  portion,  evaporated, 
responds  to  the  ferric  chloride  test  for  salicylic  acid.  Ether  has 
been  much  used  ;  chloroform  is  preferred  by  MALENFENT  (1885)  ; 
chloroform  or  benzene  by  DRAGENDOKFF  (1878).  When  the  sol- 
vent emulsifies  and  fails  to  separate  from  the  watery  layer,  as 
may  occur,  the  concentrated  aqueous  solution  (not  acidulous) 
may  be  acidified  and  mixed  with  about  twice  its  weight  of  ground 
gypsum,  enough  to  take  up  the  liquid,  the  stiffened  mass  dried 
at  a  low  heat,  pulverized,  the  powder  shaken  with  ether  or  other 


440  SALICYLIC  ACID. 

solvent,  the  mixture  filtered  and  the  residue  washed  (CAZENEUVE, 
1879).  After  evaporation  of  the  solvent,  the  residue,  if  free 
from  other  solids,  may  be  weighed  as  salicylic  acid,  or,  whether 
pure  or  not,  dissolved  in  water  and  estimated  by  the  color imetric 
method. 

(3)  Distillation  with  water,  from  acidulous  watery  solutions, 
by  boiling,  has  been  much  used  to  obtain  the  salicylic  acid  in  the 
distillate,  for  colorimetric  estimation. 1    DENNY  found  this  method 
ineffective  in  examination  of  foods.3 

(4)  Dialysis  of  salicylic  acid  has  been  resorted  to  for  its  esti- 
mation in  wine  and  beer,  milk,  and  animal  fluids  (MUTER,  1876; 
AUBRY,  1880).      Muter  recovered  from  milk  90$  by  dialysis. 
Animal   membrane  is   the   best  dialytic  septum  for  this  pur- 
pose. 

In  separation  from  wine,  cider,  and  beer  the  alcohol  may 
first  be  removed  by  evaporation  to  one-third  volume,  at  70°-80° 
C.  (REMONT,  1881).  After  extraction  with  chloroform  or  ben- 
zene, in  repeated  portions,  the  residue  from  evaporation  of  the 
solvent  may  be  dissolved  in  another  solvent  (as  with  benzene  if 
chloroform  were  first  used),  this  solution  evaporated,  and  the 
residue  taken  up  in  hot  water  to  a  definite  volume  in  ratio  to 
that  of  the  wine,  for  colorimetric  estimation.  Dialysis  is  some- 
times used  in  preliminary  treatment.  A  simple  test  may  be 
readily  made  by  shaking  50  c.c.  of  wine  with  5  c.c.  of  amyl  al- 
cohol ;  after  standing  the  layer  of  solvent  is  taken  off  and  diluted 
with  an  equal  volume  of  alcohol,  then  tested  with  a  few  drops 
of  ferric  chloride  solution  for  the  violet  color  (WEIGERT,  1880). 

In  examination  of  canned  fruits  Mr.  Denny  used  the  fol- 
lowing method  : 3  The  expressed  liquids,  with  sparing  washings, 
were  boiled  and  filtered  through  glass  wool.  To  50  c.c.  of  the 
filtrate,  acidulated,  5  to  8  c.c.  of  amyl  alcohol  were  added,  the 
whole  shaken,  the  amyl  alcohol  drawn  off,  diluted  with  an  equal 
volume  of  ethyl  alcohol,  and  this  liquid  tested  with  ferric  chlo- 
ride. 

In  examination  of  milk  for  salicylic  acid  REMONT  (1883) 
takes  20  c.c.  of  the  milk,  adds  two  or  three  drops  of  sulphuric 
acid,  and  agitates  to  break  up  the  coagulum,  when  the  mass  is 
shaken  with  20  c.c.  of  ether  and  set  aside  in  a  stoppered  tube. 
10  c.c.  of  the  ether  layer  are  taken  in  a  test-tube  marked  at 
10  c.c.,  the  ether  evaporated,  and  the  residue  of  butter  is  boiled 
with  alcohol  of  40$  strength,  and  the  liquid,  when  cold,  made 

1  Archiv  der  Pharm.  [3]  21,  296;  Jour.  Chem.  Soc.,  1884,  Abs.,  372. 

a Contributions  Chem.  Lab.  Univ.  Mich.,  1883,  2,  81. 

8  Contributions  Chemical  Laboratory,  Univ.  Mich.,  1883,  p.  80. 


SALICYLIC  ACID.  441 

up  to  10  c.c.  and  assumed  to  contain  nearly  the  salicylic  acid  in 
10  c.c.  of  the  milk.  5  c.c.  of  the  solution  are  then  filtered  into 
a  graduated  tube  for  colorimetric  estimation.  But  the  colorime- 
tric  standard  recommended  is  one  obtained  by  adding  a  known 
quantity  of  salicylic  acid  to  pure  milk — 0.1  to  0.2  gram  to  the 
20  c.c. — in  a  parallel  operation.  PELLET (1882)  takes  200  c.c.  of 
milk,  with  200  c.c.  of  water,  and  at  60°  C.  adds  1  c.c.  acetic 
acid  and  an  excess  of  mercuric  oxide  (J  c.c.  each  of  acetic  acid 
and  mercuric  nitrate  solution— G-irard,  1883).  When  cold,  the 
whey  is  filtered  out,  agitated  twice  with  100  c.c.  of  ether,  the 
ether  solution  washed,  passed  through  a  dry  filter,  and  evapo- 
rated. The  residue  is  taken  up  in  dilute  alcohol  for  colorimetric 
estimation. 

In  examination  of  butter,  10  to  50  grams  may  be  boiled 
with  alcohol  diluted  to  40  or  50  per  cent,  strength,  and  the  fil- 
tered solution,  concentrated  to  a  definite  volume,  titrated  in  the 
colorimetric  way. 

For  the  detection  of  salicylic  acid  in  the  urine,  unless  highly 
colored,  it  may  be  tested  directly  by  adding  the  ferric  chloride, 
in  a  deep  test-tube  observed  from  above.  Salicyl uric, Acid  (see 
p.  445)  gives  the  same  ferric  reaction  as  salicylic  acid.  The 
precipitate  of  ferric  phosphate  may  be  filtered  out  and  more  of 
the  reagent  added  to  the  filtrate  for  better  result.  And  if  the 
urine  be  high-colored,  it  is  to  be  made  alkaline  with  alkali  car- 
bonate, treated  with  an  excess  of  lead  nitrate  solution,  shaken 
strongly,  filtered,  and  the  filtrate  tested  with  the  ferric  chloride. 
But  in  most  cases  the  direct  test  gives  the  best  result  (SIEBOLD 
and  BRADBURY,  1881).  In  1878  Robinet  recommended  prepar- 
ing the  urine  by  precipitation  with  sufficient  lead  acetate  solu- 
tion, .adding  ferric  chloride  to  the  filtrate,  and  then  (PAGLIANI, 
18^9)  adding  dilute  sulphuric  acid,  drop  by  drop,  till  the  red 
color  of  ferric  acetate  just  disappears,  when  the  violet  test-color 
will  be  seen,  with  least  interference  from  the  sulphuric  and  ace- 
tic acids.  If  the  filtrate  be  too  dark,  basic  acetate  of  lead  solu- 
tion may  be  used  instead  of  the  normal  acetate,  otherwise  re- 
sults are  closer  after  use  of  normal  acetate. 1  With  0.002 
per  cent,  of  salicylic  acid  in  urine  a  distinct  reaction  can  just  be 
reached ;  with  0.005  por  cent,  a  very  distinct  color  is  obtained 
(Borntrager). 

f. — Quantitative. — Salicylic  acid  in  crystals  may  be  weighed 

1  BORNTRAGER,  1881:  Zeit.  anal.  Chem..  20,  87;  Jour.  Chem.  Soc.,  40, 472. 
(In  the  Chem.  Soc.  Abstract,  Bleiessigis  given  as  "impure  acetate  "  of  lead  in 
distinction  from  Bleizucker,  "pure  lead  acetate.") 


442  SALICYLIC  ACID. 

as  C7H6O3.  Neither  the  free  acid  nor  any  of  its  salts  is  insolu- 
ble enough  to  be  precipitated  for  estimation.  The  sublimate  by 
carefully  limited  heat  (see  a)  could  be  weighed,  instead  of  the 
crystals.  But  a  colorimetric  method  by  ferric  chloride,  in  com- 
parison with  depth  of  color  from  known  solution  of  salicylic 
acid,  was  given  by  DR.  MUTER,  in  1877,  as  follows : l 

The  solutions  required  are .  (1)  of  pure  salicylic  acid  (by  dia- 
lysis and  reerystallization)  1  gram  in  water  to  make  1000  c.  c. ; 
(2)  of  ferric  chloride  such  a  dilute  solution  that  1  c.c.,  treated 
with  50  c.c.  of  the  standard  solution  of  salicylic  acid,  just  cease 
to  give  increase  of  intensity  of  color  before  the  last  drop  or  two 
of  last-named  solution  is  added.— If  commercial  salicylic  acid  is 
to  be  valued,  dissolve  1  gram  in  water  to  make  1  liter,  and  take 
50  c.c.  in  a  Nessler  tube  (or  a  seven  or  eight  inch  test-tube).  Of 
any  solution  recovered  by  separation,  take  50  c.c.,  or  a  quantity 
to  dilute  to  50  c.c.,  in  the  tube  mentioned.  Add  1  c.c.  of  the 
ferric  chloride  solution  to  the  50  c.c.  of  the  solution  to  be  esti- 
mated. In  one  or  more  tubes  of  same  width  take  now,  in  each. 
1  c.c.  of  ferric  chloride  solution  and  as  many  c.c.  of  the  standard 
solution  of  salicylic  acid  as  deemed  necessary,  and  dilute  to  51 
c.c.  After  five  minutes,  or  if  acetic  acid  be  present  after  ten 
minutes,  compare  the  color  in  the  tubes.  Repeat  the  trial  with 
the  standard  solution  until  a  depth  of  tint  is  obtained  the  same 
as  that  from  the  solution  under  estimation.  Then,  in  the  trial 
giving  equality  of  tint,  the  c.c.  of  the  standard  salicylic  acid  so- 
lution X  0.001  —  grams  of  salicylic  acid  in  the  portion  taken  for 
estimation.  And  if  the  solution  under  estimation  be  that  of 
1  of  commercial  acid  made  up  to  1000,  then  c.c.  of  standard  acid 
X  2  =  per  cent,  desired. 

Salicylic  acid,  with  ferric  chloride,  has  been  proposed 
(WEISKE,  1876)  as  an  indicator  in  acidimetry.  It  is  much  less 
definite  than  litmus  (MoHR,  ''  Titrirrnethode  ").  The  violet  color 
deepens  in  intensity  as  the  neutral  point  is  approached,  but  as 
soon  as  this  point  is  passed  the  color  pales  to  reddish-yellow. 
Apparently  the  titration  of  salicylic  acid,  with  volumetric  solu- 
tions of  soda,  using  ferric  chloride  as  an  indicator,  should  give 
fairly  good  results,  more  trustworthy  if  the  volumetric  alkali  be 
standardized  by  a  known  solution  of  pure  salicylic  acid; — an  ^ 
solution  =  1.38  gram  salicylic  acid  in  a  liter.  Each  c.c.  of  al- 
kali normal  solution  =  0.138  gram  of  salicylic  acid. 

g. — Impurities,  and  tests  of  purity. — Color  may  be  due  to 
coal-tar  compounds,  or  to  iron  as  ferric  salicylate.  Carbolic 

1  Analyst,  i,  193. 


SALICYLIC  ACID. 


443 


acid  is  for  medicinal  purposes  a  quite  dangerous  impurity,  but 
80  obvious  that  it  is  not  likely  to  be  neglected  by  the  manu- 
facturer or  tolerated  by  the  purchaser,  and  it  is  more  liable  to 
arise  in  minute  quantities  from  decomposition  of  an  article  not 
pure  enough  to  be  stable.  The  cresotic  acids  (see  Sources, 
p.  434)  are  probably  the  most  abundant,  and  it  may  be  feared 
the  most  serious,  impurities  in  the  salicylic  acid  made  from  car- 
bolic acid.  In  1878  Mr.  Williams,1  by  investigations  not  com- 
pleted, reported  from  15  to  25  per  cent,  of  "  secondary  "  or  al- 
lied acids,  much  more  soluble  than  true  salicylic  acid  but  less 
soluble  than  para- hydroxybenzoic  acid,  in  "  the  best  "  artificial 
salicylic  acid  of  the  market.  In  1883  Dr.  Squibb2  said  that 
the  better  grades  of  well- crystallized  acid  of  the  market  con- 
tained 4  to  5  per  cent.  c '  of  something  which  is  not  salicylic 
acid  "  but  is  inferred  to  be  homologous  acid,  and  "  not  present 
in  so  large  a  proportion  as  when  Mr.  Williams  wrote."  The 
homosalicylic  or  cresotic  acids  are  described  as  "  deceptively 
like  salicylic  acid,"  and  "behaving  with  solvents  and  reagents 
almost  exactly  like  salicylic  acid."  8  On  the  contrary,  the  two 
isomeric  hydroxybenzoic  acids  are  so  much  more  soluble  in 
water  than  true  salicylic  acid  that  they  must  be  well  removed 
from  the  recrystallized  acid.4  Williams  and  others  remove  sali- 

lPhar.  Jour.  Trans.  [3]  8,  785;   Pro.  Am.  Pharm.,  26,  536. 

9  Ephemrris,  I,  412. 

3  "  Watts's  Diet.,"  3d  sup.,  pp.  584,  2024. 

*  The  following  table  gives  properties,  so  far  as  found,  for  (1)  the  two 
isomers  of  salicylic  acid ;  (2)  those  of  the  next  homologues  of  salicylic  acid 
which  are  found  to  be  formed  from  cresols  by  Kolbe's  method,  and  have  been, 
termed  cresotic  acids;  and  (3)  three  reported  homologues  removed  two  places 
from  salicylic  acid,  or  xylenol products.  (See  the  foot-note  under  Sources.) 


Melting, 

Vaporizing. 

Solubility 
in  water 
(parts). 

In 
alcohol. 

In 

chloro- 
form. 

Ferric  reac- 
tion. 

1.  Ilydroxybenzoic  acids  : 
Salicylic  acid  (ortho)  . 

156° 

With  eteam. 

444 

2.4 

80 

Violet. 

Metahydroxybenzoic. 
Parahydroxybenzoic  . 

200° 
210° 

Not  with  eteam. 

108  at  18°  C. 
126  at  15°  C. 

Freely. 

Little, 

No  color. 
Yellow  pre. 

2.  llydroxytoluic  acids  : 
CO2H  :  OH  :    CH3  = 

(Cresotic  or  "  homo- 

salicylic  acids  ") 
1  :2:  3  

160° 

With  steam. 

Freely. 

Violet. 

1:2:4  

173° 

1:2:5 

151° 

<i         u 

Easily. 

Easily. 

14 

8.  Hydroxyxylenic  acids: 

E.  Gunter,  1884.    (1). 

170.5° 

Not  with  steam. 

No  color. 

(2) 

144° 

With  steam. 

Blue. 

(3) 

153° 

• 

.... 

No  color 

444  SALICYLIC  ACID. 

cylic  acid  from  its  homologous  acids,  in  a  purification  of  the  arti- 
ficial salicylic  acid  of  the  market,  by  the  comparative  insolubi- 
lity of  the  calcium  salicylate,  as  follows  :  The  acid  is  treated  in 
boiling  water  solution  with  carbonate  of  calcium  in  excess,  the 
solution  of  salicylate  crystallized  by  cooling  of  the  filtrate,  the 
salt  recrystallized  repeatedly,  and  finally  acidified  with  hydro- 
chloric acid,  to  obtain  true  salicylic  acid.  The  mother-liquors 
from  the  calcium  salicylate,  acidified  with  hydrochloric  acid, 
gave  the  homosalicylic  acids,  not  fully  examined.  Hydrochlo- 
ric acid  and  chlorides  are  obviously  incidental  impurities.  The 
pharmacopoeia  of  France  (1884)  places  glycerin  among  the  im- 
purities, and  as  falsifications  names  sugar,  starch,  silica,  calcium 
sulphate,  potassium  disulphate,  etc. 

Carbolic  acid  is  likely  to  be  revealed  by  the  odor  on  opening 
a  bottle.  Closer  examination  may  be  made  by  warming  about 
a  gram  (15  grains)  in  a  (dry)  test-tube  immersed  for  a  quarter  of 
an  hour  in  water  a  little  below  boiling  temperature,  when  no- 
odor  of  carbolic  acid  should  be  obtained.  Carbolic  acid  may  bo 
separated  and  concentrated  by  making  a  solution  with  excess  of 
sodium  carbonate  and  water,  shaking  with  ether,  and  evaporating 
the  ethereal  solution  (Ph.  Germ.,  1882).  A  test  by  the  chlo- 
rate of  potassium  and  hydrochloric  acid  reaction  for  phenol,, 
adopted  in  the  U.  S.  Ph.,  1880,  has  been  said  to  give  a  pinkish 
coloration  with  the  best  obtainable  medicinal  grades  of  acid 
(SQUIBB,  1883).  ALM^  (1877)  employs  chlorinated  soda  solu- 
tion and  ammonia,  avoiding  an  excess  of  the  chlorinated  solution, 
and  adding,  last,  ammonia  to  an  alkaline  reaction — a  blue  colorT 
red  in  acidulous  and  blue  in  alkaline  reaction,  reveals  l-5000th 
of  phenol  at  once,  l-50000th  after  twenty-four  hours. 

For  organic  matters,  indeterminate,  treatment  with  sulphuric 
acid,  without  heat,  is  official  in  the  U.  S.  and  German  pharma- 
copoeias.1 One  part  of  the  salicylic  acid  (0.2  to  0.3  gram)  (3  to  5 
grains),  with  15  parts  concentrated  sulphuric  acid  (U.  S.  Plv),  6 
parts  (Ph.  Germ.),  6  to  10  parts  (Hager),  the  mixture  stand- 
ing 15  minutes  (U.  S.  Ph.),  without  specification  of  time  (Ph. 
Germ.),  should  give  no  color  (U.  S.  Ph.),  should  be  nearly  with- 
out color  (Ph.  Germ.),  with  the  6  to  10  parts  of  sulphuric  acid 
should  give  a  colorless  or  pale  yellow  solution,  brown  colors 
indicating  insufficient  purity  (Hager,  in  "  Commentar ''). — For  or- 
ganic matters  and  iron  an  evaporation  of  the  alcoholic  solution 
has  been  prescribed  by  Kolbe  (1876,  and  von  Hey  den,  1879),  and 

1-This  test  was  advised  by  EAGER  in  1876:  Phar.  Centrafh.,  17,  434;  and 
with  additional  confidence  in  1883:  "Commentar,"  194. 


SALICYLURIC  ACID.  445 

is  official  in  the  pharmacopoeias,  U.  S.,  Br.,  Germ.  "A  satu- 
rated solution  in  absolute  alcohol,  when  allowed  to  evaporate 
spontaneously  in  an  atmosphere  free  from  dust,  should  leave  a 
perfectly  white  crystalline  residue,  without  a  trace  of  color  at 
the  points  of  the  crystals  (absence  of  [certain]  organic  impuri- 
ties ;  also  of  iron)  "  (U.  S.  Ph.)  Prof.  Kolbe  directs  to  dissolve 
3  to  5  grains  (50  to  75  grains)  of  the  acid  in  the  smallest  possible 
quantity  of  absolute  alcohol,  and  pour  the  clear  solution  on  a 
watch-glass  over  a  white  surface.  Mechanical  impurities  will  be 
perceptible  at  once.  The  solution  is  left  to  evaporate  in  an 
atmosphere  free  from  dust,  especially  from  iron,  and  crystals  in 
efflorescence  are  obtained.  If  points  of  crystal-  borders  are 
brown,  resinous,  or  phenol-like,  impurity  is  indicated  ;  if  light 
yellow,  organic  dye  ;  if  violet  or  pink,  iron.  Hager  insists  that 
this  test  is  much  less  trustworthy  than  that  with  concentrated 
sulphuric  acid.  —  For  hydrochloric  acid  and  chlorides,  "  a  solu- 
tion in  10  parts  of  alcohol,  mixed  with  a  few  drops  of  nitric  acid, 
should  not  become  turbid  on  addition  of  a  few  drops  of  test  so- 
lution of  nitrate  of  silver."  —  For  non-volatile  matters  test  is 
readily  made  by  vaporization,  which  should  leave  no  residue. 
Hager  directs  to  heat  0.15  to  0.2  gram  (2  to  3  grains)  in  a  test- 
tube  |  inch  wide,  by  moving  it  through  the  flame,  when  at  last 
no  stain  should  be  left.  In  the  vaporization  odor  of  phenol  is 
usually  developed. 


SALICYLURIC  ACID  —  C9HgNO4=C6H4  .  CO.  NH.  CH2.  CO2H. 

OH.  —  Occurs  in  the  urine  after  administration  of  salicylic  acid 
(&,  p.  436).  Crystallizes  in  fine  needles.  Melts  at  160°  C.,  and  de- 
composes at  170°  C.  ,  with  vaporization  of  salicylic  acid.  Sparingly 
soluble  in  cold  water,  easily  soluble  in  alcohol,  soluble  in  ether, 
less  soluble  in  a  mixture  of  ether  and  benzene  than  salicylic  acid 
is  (BECK,  1876),  and  thereby  separated.  Forms  stable  salts.  With 
ferric  chloride  gives  deep  violet  color. 


SALICYLATE  OF  SODIUM.—  C6H4  .  CO2lSra  .  OKa  .  £(H  2O)  =  338. 
—  For  description  and  tests  of  purity  see  U".  S.  Ph.,  1880.  Its  re- 
action is  not  acidulous  if  it  be  wholly  free  from  uncombined 
salicylic  acid.  Even  when  kept  in  tight  bottles,  as  required,  the 
salt  is  liable  to  acquire  color  by  storing.  According  to  Hager, 
this  is  due  to  formation  of  phenol.  Both  the  ammonia  and  the 
carbon  dioxide  of  the  air  induce  decomposition  to  the  extent  of 
giving  color.  In  operating  with  the  salt,  traces  of  iron  in  filter- 
paper  and  in  waters  must  be  avoided.  The  aqueous  solution  is 
instable,  and  darkens  on  standing.  Mr.  Martin  (1883)  states 


446  STRYCHNOS  ALKALOIDS. 

that  the  addition  of  thiosulphate  (hyposulphite)  of  sodium.  1 
part  to  123  parts  of  the  salicylate,  prevents  the  coloration  of  the 
latter  in  aqueous  solution. — Carbolic  acid  as  an  impurity  mar  be 
recognized  bj  its  odor,  the  better  on  warming,  not  above  about 
90°  C.  It  may  be  separated  for  identification  by  shaking  the 
aqueous  solution,  exactly  neutralized,  with  ether,  "and  evaporat- 
ing the  latter  at  ordinary  temperature. 

SALICYLURIC  ACID.     See  p.  445. 

SANDAL  RED.     See  COLORING  MATTEBS,  pp.  189,  191. 

STE ARIC  ACID.     See  FATS  ASD  Cms,  p.  240. 

STRYCHNOS  ALKALOIDS.— The  alkaloids  found  in 
the  Strychnos  nux-vomica,  S.  Ignatii,  S.  colubrina,  and  Upas 
Tieute,"of  the  natural  order  Loganiaceae. 

Strychnine,   C^H^X^^.      PELLETIER  and    CAVENTOU,    1S18. 

p.  447. 

Brueine,  C23H26X2O4.  PELLETIEB  and  CAVEXTOU.  1819,  p.  483. 
Igasurine.  DESXOEK,  1853 ;  existence  called  in  question  by  SCHCT- 

ZEXBEEGEK,  1858 1  Ann.   Ckim.  Phys.  [3]  54,   65.*    SHEN- 

STOXE,  18S1 :  Jour.  Chem.  Sac ,  39,  453. 

Constitution  of  Strychnine  and  Brucine. — Brucine  has  the 
elements  of  dimethoxy-strychnine,  C21R20(OCH3)2X2O2.  SHEX- 
grroxE,1  and  later  HAXSSEX,*  have  shown  it  well-nigh  certain  that 
brncine  actually  is  dimethoxy-strychnine,  and  are  working  upon 
the  problem  of  artificial  conversion  of  the  one  into  the  other. 
HAXSSEX  finds  the  body  C16H18X2O2  to  be  common  to  both 
strychnine  and  brucine,  and  to  be  changed  by  oxidation  with 
sulphuric  and  chromic  acids  into  C16H18]S2O4.  The  announce- 
ment of  SONXEXSCHEIS,*  in  1875,  that  brucine  is  converted  into 
strychnine  by  treatment  with  nitric  acid,  carbon  dioxide  being 
evolved,  has  not  been  confirmed,  and  this  conversion  is  denied 
by  HAXBIOT  (1884).4  The  physiological  relations  of  brucine  and 
strychnine  have  been  investigated  by  BRUXTOX,*  with  comparison, 
also,  with  methyl-strychnine,  a  product  under  trial  as  to  its  effects. 

'WS-85:  Jour.  Chen.  Soc.,  43,  101;  47,  139;  Ber.  d.  ehem.  Get,  17. 
2>4c*. 

•1884-86:  Ber.  d.  cheat.  (?«.,  17,  2849;  18.  777,  1917;  19,  520;  Jour. 
Chem.  Sor..  48,  276.  819,  1146;  50,  564. 

*F.  L.  SoxxEXSCHEor:  Ber.  d.  them.  Get.,  8,  212;  Jour.  Chem.  Soc.,  28, 
771. 

4  Gmpt.  rend.,  97,  267;  Jour.  Chem.  Soc.,  46,  88. 

M885:  Jour.  Chem.  Soc.,  47,  143. 


STRYCHNINE.  447 

Yield  of  Strychnos  Alkaloids.— Total  alkaloids :  1.65  to 
2.88  per  cent.  (DRAGENDORFF,  1874  *).  More  than  is  generally 
supposed,  the  richest  specimens  reaching  nearly  4  per  cent. 
(DL-XSTAX  and  SHOKT,  1883-85,  by  their  own  method*).  Dr.  A. 
ti.  Lroxs,  in  1885,*  stated  the  results  of  twelve  specimens,  from 
2.68  to  4.89  per  cent.,  giving  a  mean  of  3.16  per  cent.  Of 
strychnine  alone,  0.96  to  1.39  per  cent,  in  the  results  of  a  few 
lots  (DRAGEXDORFF,  1874).  As  a  generally  accredited  statement, 
from  analyses  older  than  the  recent  methods,  strychnine  is  found 
in  Ignatius  bean  as  high  as  1.5  per  cent. ;  in  nnx-vomica  seeds 
with  an  average  of  0.5  per  cent.  The  statements  of  Dunstan 
and  Short  are  given  in  foot-note  below.  Methods  of  analytical 
separation  of  strychnine  from  brucine,  in  use,  are  not  well  assured. 

Constituents  of  Nux-vomica,  other  than  the  Alkaloids. — 
In  combination  with  the  alkaloids,  Strychnic  or  Igasuric  Acid, 
so  named,  is  in  fact  an  iron- greening  tannic  acid  (Honx,  Arch, 
der  Phar.,  202,  137). — A  glucoside,  Loganin,  CggEL^O^,  was 
discovered  in  nux-vomica  by  DUNSTAN  and  SHORT  in  1884.4  In 
the  seeds  of  Strychnos  nux-vomica,  and  in  pharmaceutical  prepa- 
rations made  therefrom,  it  is  present  in  small  proportion  :  in  the 
pulp  of  the  frnit  of  Strychnos  nux-vomica  it  was  found  to  the 
extent  of  4  or  5  per  cent.  Loganin,  warmed  with  sulphuric 
acid,  gives  a  fine  red  color,  which  on  standing  develops  into  a 
purple — a  color-result  not  unusnal  to  glucosides.  By  boiling 
with  dilute  sulphuric  acid  a  glucose  and  a  body  named  logane- 
tin  were  formed. 

STRYCHNINE. — C21EL^N2O2  =  334.  Crystallizes  anhydrous. 
Constitution,  p.  446  ;  Yield  in  nux-vomica,  given  above. 

Strychnine  is  identified  by  the  chemical  tests  of  the  fading 
purple,  and  the  crystallization  of  the  dichromate  and  free  al- 
kaloid, and  by  the  physiological  tests  of  tetanic  effect  and  bit- 
terness (b  and  d).  Microscopic  recognition,  a  and  d.  Its  limits 
of  quantity  are  indicated  by  the  limit  of  response  in  the  fading- 
purple  test  (d)  and  in  the  physiological  tests  (b).  Solubilities, 

1  "  Werthbestimmnng,"  p.  64. 

*  Phar.  Jour.  Trans.  [3]  12,  1055;  15.  157;  4m.  Jour.  Phar.,  55,  467. 
In  the  seeds  of  Cevlon  nux-vomica  these  authors  report  as  follows  (Phar.  Jour. 
Trans.  [3]  15, 1): 

No.  1,    1.52  per  cent,  strychnine,  2.95  per  cent,  brncine,  4.47  per  cent,  total 
"    2,    1.78      "  "  3.16      "  "         4.94 

"    3,     1.71       "  "  3.63      "  ««          5.31 

"    4,     1.68      "  •«  2.86      ••  "          4.54        "  •• 

*Proc.  Mteh.  State  Phar.  As*oc.,  2,  173. 
*Phn  .  J.rnr.  Trans.  [3]  14, 1025;  Am.  Jour.  Phar.,  56,  431. 


448  STRYCHNOS  ALKALOIDS. 

c,  p.  451.  Separations  (e)  by  solvents  immiscible  with  water 
(p.  456),  from  Nux-vomica  (p.  456),  from  preparations  of  the 
latter  (p.  457),  from  Biucine  (p.  458),  from  tissues  and  foods  in 
cases  of  poisoning  (p.  458),  from  the  urine  (p.  460),  from  alco- 
holic beverages  (p.  400).  Limits  of  recovery  from  tissues,  etc., 
p.  461.  In  what  organs  found  in  cases  of  poisoning,  J ;  how 
long  after  death  recoverable,  e  (p.  461).  Estimated  gravimetri- 
cally  and  volumetrically,  f.  Tests  for  impurities,  g. 

a. — Colorless  or  transparent  octahedra,  or  needles,  or  prismat- 
ic crystals ;  or  a  crystalline  white  or  dull  white  powder.  By 
spontaneous  evaporation  of  a  few  drops  of  an  alcoholic  solution, 
on  a  glass  slide,  a  characteristic  microscopic  field  is  obtained, 
and  recognized  by  comparison  with  a  field  from  known  strych- 
nine under  parallel  treatment.  The  crystals  may  also  be  ob- 
tained on  diluting  a  few  drops  of  the  alcoholic  solution  with 
particles  of  water  applied  to  the  slide  by  a  pointed  glass  rod. 

Strychnine  melts  at  about  300°  C.  In  the  "  subliming  cell" 
at  221°  C.  (BLYTH,  1878).  A  microscopic  sublimate  of  needles 
is  obtained  at  169°  C.  (BLYTH,  1878).  Sublimes  in  part  un- 
changed, giving  a  sublimate  recognized  under  the  microscope 
(HELWIG,  1864).1 

Strychnine  Sulphate,  (C2  JI22N2O2)2H2SO4  .  6H2O  =  874 
(COLEMAN,  1883),  is  efflorescent  in  dry  air;  at  about  135°  C. 
melts  and  (near  200°  C.,  RAMMELSBERG,  1881)  parts  with  its 
water  of  crystallization  (12.36$).  Crystallizes  in  prisms.  Crys- 
tals with  7H2O  have  been  reported,  and  crystals  with  5H2O 
are  obtained  from  alcoholic  solution. — An  acid  sulphate, 
C21H22N2O2.H2SO4.2H2O,  crystallizes  in  fine  needles.— The 
nitrate,  normal,  crystallizes  anhydrous,  in  groups  of  silky  nee- 
dles.— The  hydrochloride,  normal,  with  1^H2O,  crystallizes  in 
soft  needles  or  in  prisms,  and  readily  effloresces. 

~b. — The  bitterness  of  strychnine  is  stated  to  be  perceptible 
in  a  solution  diluted  to  600000  or  700000  parts.  The  bitter 
taste  is  followed  by  some  degree  of  metallic  after-taste. — In 
effect,  strychnine  is  a  tetanic  poison,  to  animals  as  well  as  man. 
Locally  it  has  a  very  slight  degree  of  irritation.  Its  tetanic  ef- 
fects are  due  to  its  action  on  the  gray  nerve-tissue  of  the  spinal 
cord.  It  is  in  some  part  antagonized  by  chloral  hydrate,  aconite, 
hydrocyanic  acid,  and  nicotine,  but  these  do  not  serve  as  anti- 
dotes to  its  poisonous  action. 

1  BLYTH:  Jour.  Chem.  Soc.,  33,  316.  HELWIG:  Zeitsch.  anal.  Ghem., 
3,46. 


STRYCHNINE.  449 

The  smallest  known  fatal  dose  for  an  adult  person  is  half  a 
grain.  With  adults  in  ordinary  varying  degrees  of  susceptibi- 
lity, the  administration  of  from  |-  to  2  grains  (0.03  to  0.13  gram) 
is  likely  to  cause  death,  unless  this  result  be  prevented  by  special 
conditions  or  by  treatment.  Recovery  has  occurred  in  cases  of 
poisoning  by  doses  of  from  3  to  20  grains,  and  may  occur  irre- 
spective of  the  quantity  taken.  The  Ph.  Germ,  places  the  maxi- 
mum single  medicinal  dose  of  the  nitrate  at  0.01  gram  (-J-  grain) ; 
the  maximum  daily  quantity,  0.02  gram. 

With  frogs  Marshall  Hall  found  distinctive  effects  from  the 
immersion  of  the  animal  in  a  solution  of  strychnine  at  a  limit  of 
0.0002  grain  (0.000013  gram) ;  Harley,  by  injection  into  the 
lungs  of  very  small  frogs,  obtained  spasms  from  as  little  as 
0.00006  grain  (0.000004  gram).  By  carrying  the  solution,  about 
2  grains  in  amount,  into  the  stomach  of  a  frog  (Rana  Halecina) 
fresh  from  the  pond,  and  of  from  15  to  50  grains  w eight, 
Wormley  obtained,  from  00002  grain  (0.000013  gram)  of  strych- 
nine, distinctive  symptoms  in  from  10  to  30  minutes  ;  from  0.002 
grain  (0.00013  gram),  symptoms  in  3  or  4  minutes,  and  death  in 
15  to  30  minutes  ;  from  0.02  grain  (0.01)13  gram)  of  strychnine, 
immediate  spasms  and  death  in  about  8  minutes.  With  0.00007 
grain  (0.000005  gram)  of  strychnine,  symptoms  were  obtained 
in  some  of  the  very  small  animals  in  50  minutes ;  in  other  ani- 
mals no  symptoms  were  obtained. 

No  chemical  change  of  strychnine,  in  its  course  through  the 
living  body,  has  as  yet  been  demonstrated.  In  some  part,  or  at 
some  rate,  it  may  suffer  oxidation  or  conversion  in  the  body,  as 
Plugge  and  others  have  believed.  In  a  considerable  part,  at 
least,  it  is  in  many  cases  excreted,  unchanged,  in  the  urine.  In 
other  cases  of  poisoning,  analysis  of  the  urine  has  failed  to  reveal 
it.  KRATTER  (1882)  found  strychnine  in  the  urine  in  half  an 
hour  after  the  administration  of  \  grain  (0.0075  gram)  of  strych- 
nine nitrate ;  and  it  continued  to  be  so  excreted  for  24  hours. 
When  administered  several  times  in  succession,  it  was  3  days 
after  the  last  ingestion  before  the  alkaloid  disappeared  from  the 
urine.  HAMILTON  (New  York,  1867)  reported  the  finding  of 
strychnine  in  the  urine  on  the  morning  after  the  patient  wTas 
poisoned.  RAUTENFELD  (1884,  Dor  pat)  repeatedly  obtained 
strychnine,  in  crystalline  form,  from  the  urine.  McADAM  found 
it  in  the  urine  of  a  dog  nine  minutes  after  the  administration 
of  half  a  grain,  and  before  symptoms  of  poisoning  appeared. 
Usually,  however,  it  is  not  to  be  found  in  the  urine  of  animals 
quickly  killed  by  it.  In  two  cases  of  dogs,  with  death  after, 
respectively,  40  and  100  minutes,  WORMLEY  failed  to  find  the 


450 


STRYCHNOS  ALKALOIDS. 


poison  in  the  urine. — In  the  liver  it  is  retained  to  an  extent 
greater  than  has  been  found  in  any  other  organ  (DRAGENDORFF 
and  MASING-,  HUSEMANN,  ANDERSON).  In  other  organs  and  in 
the  tissues  of  poisoned  animals  its  recovery  by  analysis  is  very 
uncertain.  When  death  of  the  animal  very  shortly  follows  the 
administration,  it  is  in  many  cases  to  be  found  in  the  blood. 
DRAGENDORFF  concludes  from  experiments  under  his  direction 
that  strychnine  very  quickly  leaves  the  blood  and  becomes  re- 
tained in  the  liver.1  G.  A.  KIRCHMAIER,  in  experiments  made 
under  the  observation  of  the  author,  found  that  strychnine  was 
by  no  means  uniformly  recovered,  even  to  a  qualitative  extent, 
from  the  blood  of  animals  quickly  poisoned  with  the  alkaloid, 
nor  from  any  of  their  organs  remote  from  the  point  of  introduc- 
tion." (As  to  limits  of  analysis,  in  recovery  of  the  alkaloid,  see 
under  Separations,  e.) 

'"Meine  Erfahrung  ilber  diesen  Gegenstand  lasst  vermuthen,  dass  das 
Strychnin  sehr  schnell  dem  BliUe  entzogen  und  in  der  Leber  zuruckgehalten 
werde,  von  wo  aus  es  nur  sehr  langsam  wieder  in  die  allgemeine  Saftcircula- 
tion  gelangt,  urn  rait  dem  Harn  aus  der  Korper  entfernt  zu  werden.  Es  lasst 
sich  wenigstens  bei  Hunden  und  Katzen  nicht  dafiir  einstehen,  dass  man,  selbst 
wenn  der  Tod  bald  nach  Darreichung  das  Giftes  erfolgt,  im  Blute  oder  den 
blutreichen  Organen  (ausschliesslich  der  Leber)  das  Gift  nachweisen  ko'nne. 
Bei  Versuchen,  die  unter  meiner  Leitung  angestellt  wurden,  erhielt  G.  P. 
Masing  bald  ein  positives,  bald  ein  negatives  Resultat,  ohne  Anhaltspunkte  filr 
eine  Erklarung  dieser  Verschiedenheiten  zu  gewinnen  "  ('  Ermittelung  von 
Giften,"  p.  249). 

2  Experiments  by  administration  to  cats,  with  dissection  and  analysis 
beginning  not  later  than  12  hours  after  death  occurred  from  the  action  of 'the 
poison :  G.  A.  KIRCHMAIER,  1883:  Contributions  Chem.  Lab.  Univ.  Mich.,2,p.  91. 


Strychnine  given. 

How  administered. 

Time  before 
deaUi. 

Dissection. 

No.  1... 
'    2...   . 
•    3...   . 
'    4...   . 
*    5...   . 
'    6...   . 

One-fourth  grain. 
One-sixth  grain. 
One-eighth  grain. 
One  thirty-second  grain. 

One-sixtieth  grain. 

Injection  into  the  back. 

"           "         breast. 
In  saphenous  vein. 
By  the  stomach. 

2     minutes. 
2* 

f* 

11 
20 

In  %  hour. 

In^     " 

In  12  hours. 
At  once. 

In  cases  Nos.  3  and  4  chloroform  was  administered  before  the  poison  was 
given. 


Liver. 

Kidneys. 

Blood. 

Heart. 

Muscle. 

Muscle  near 
puncture. 

Stomach. 

No.  1. 

Not  found  . 

Not  found. 

Not  found. 

Not  found. 

Not  found. 

Found. 

Not  found. 

2. 

44                 41 

44       41 

44                 44 

44                   i 

4' 

44                 44 

3. 

Found. 

Found. 

Found. 

14                   < 

(4                 44 

4. 

Not  found. 

Not  found. 

44                 44 

5. 



Found. 

6. 

"       " 

.... 

... 

.... 

Not  found. 

STRYCHNINE.  451 

c. — Strychnine  is  soluble  in  67000  parts  of  water  at  15°  C. ; 
in  8333  parts  at  ordinary  temperature  (WORMLEY)  ;  in  2500  parts 
of  boiling  water  ;  in  110  parts  of  alcohol  at  15°  O. ;  in  207  parts 
of  absolute  alcohol  or  400  parts  of  common  whiskey  (WOKMLEY)  ; 
in  12  parts  of  boiling  alcohol ;  in  about  500  parts  diluted  alcohol 
of  sp.  gr.  0.941  and  in  2617  parts  of  sp.  gr.  0.970  (PRESCOTT  and 
SMITH,  1878) ;  in  1400  parts  of  absolute  ether  at  ordinary  tempo 
rature  (WORMLEY),  or  in  1250  parts  of  commercial  ether  (DitA- 
GENDORFF) ;  in  6  to  8  parts  of  chloroform;  in  140  parts  of 
benzene  (sp.  gr.  0.878)  ;  slightly  soluble  in  petroleum  benzin 
(DRAGENDORFF),  requires  12500  parts  (WORMLEY)  ;  soluble  in 
122  parts  of  amyl  alcohol;  in  300  parts  of  glycerin  (CASS  and 
GARST)  ;  somewhat  soluble  in  certain  essential  oils  ;  sparingly 
soluble  in  ammonia-water,  not  soluble  in  solutions  of  fixed  alka- 
lies. Fine  octahedral  crystals  are  obtained  from  the  benzene  so- 
lution. 

Strychnine  in  alcoholic  solution  gives  a  decided  alkaline  reac- 
tion to  test-papers  ;  and  it  forms  stable  salts,  mostly  of  a  neutral 
reaction. — Strychnine  sulphate  (a,  p.  448)  is  soluble  in  42.7  parts 
of  water  at  15°  C.  (COLEMAN,  1883) ;  very  freely  soluble  in  boil- 
ing water ;  in  60  parts  of  alcohol  at  ordinary  temperature,  or  2 
parts  boiling  alcohol ;  insoluble  in  ether,  or  chloroform,  or  ben- 
zene, or  amyl  alcohol ;  soluble  in  26  parts  of  glycerin. — /Strych- 
nine nitrate  is  soluble  (Ph.  Germ.)  in  90  parts  of  cold  or  3  parts  of 
boiling  water,  and  in  70  parts  of  cold  or  5  parts  of  boiling  alco- 
hol.—  The  hydrochloride  is  soluble  in  50  parts  of  cold  water. 

d.  —  Qualitative  tests. — The  fading  purple  :  If  strychnine  or 
one  of  its  ordinary  salts,  purified  from  non-alkaloidal  matter,  in 
a  film  of  dry  residue  or  a  particle  of  dry  mass,  on  a  white  porce- 
lain surface,  be  moistened  with  pure  concentrated  sulphuric  acid, 
in  the  cold,  no  coloration  occurs.  If  now  a  just  visible  fragment 
of  crystallized  potassium  dichromate,  taken  on  the  end  of  a  nar- 
row glass  rod,  be  placed  for  a  moment  in  the  moistened  film  of 
the  test  material,  and  then  drawn  out  through  it,  a  distinct  purple 
to  blue  color  appears,  soon  changing  to  reddish  yellow  tints,  and 
fading  away  into  the  slight  colors  due  to  the  dichromate  itself. 
The  area  of  moistened  film,  taken  at  first,  need  not  be  over  a 
fourth  of  an  inch  in  diameter,  and  the  liquid  is  drawn  in  one 
direction  only,  toward  the  side  of  the  dish,  as  the  dichromate  is 
carried  through  it.  in  repetition  of  the  trial. — The  reaction  is 
obtained  by  the  sulphuric  acid  and  an  oxidizing  agent,  and  lead 
peroxide,  ceroso-ceric  oxide,  manganic  hydroxide,  potassium  per- 
manganate, and  potassium  ferricyanide  have  severally  been  used 


452 


STRYCHNOS  ALKALOIDS. 


for  this  purpose.1  The  permanganate,  cerium  oxide,  and  ferri- 
cyanide  are  usually  mixed  with  the  sulphuric  acid  before  the 
test :  one  part  of  permanganate  in  2000  parts  of  the  acid,  etc. 
But  if  this  be  done  the  film  must  be  separately  tested  with 
sulphuric  acid  alone.  The  proportion  of  oxidizing  agent  must 
be  minute  in  testing  for  minute  quantities  of  the  alkaloid.  The 
color  given  by  the  oxidizing  agent  itself,  in  the  sulphuric  acid, 
must  be  observed.  If  traces  of  non-alkaloidal  matters  are 
present,  a  portion  of  similar  matters  is  subjected  to  the  same 
test,  and  any  shades  of  color  developed  are  to  be  taken  into  the 
account.  Dichromate  in  sulphuric  acid  has  a  slight  color,  from 
the  yellowish-red  of  the  dichromate  itself  to  the  chromic  sulphate 
formed  by  reduction.  Permanganate  presently  becomes  green 
in  sulphuric  acid.  These  tints  do  not  resemble  the  fading  pur- 
ple, and  in  use  of  the  proper  minute  quantities  of  the  oxidizing 
agent  they  do  not  obscure  the  strychnine  reaction,  or  not  until 
the  extreme  limit  of  recognition  of  the  latter  is  reached. — It  is 
to  be  remembered  that  the  evidence  of  strychnine  depends  upon 
the  joining  of  three  results :  (1)  no  coloration  by  the  sulphuric 
acid,  (2)  a  blue  or  purple  color  when  the  oxidizing  agent  takes 
effect,  (3)  the  fading  of  the  blue  or  purple  color. — The  use  of  a 
good  hand-magnifier  adds  efficiency  to  the  test,  but  all  the  re- 
sults should  be  unmistakable  to  the  eye  without  special  aids. 

By  the  manipulation  with  the  dichromate  as  above  given  in 
detail,  and  applied  to  a  residue  from  1  c.c.  of  solution,  a  good 
and  strong  color  can  be  obtained  from  0.0000025  gram  (0.000037 
grain)  of  strychnine.3 

1  As  to  special  effects  of  vanadic  acid  in  this  test,  MANDELIN,  1883.     As  to 
a  certain  product  of  this  oxidation,  see  p.  446. 

2  In   detailed    experiments  the  following  results    were   obtained   (G.   A. 
KIRCHMAIER,    1883:    Contributions   Chem.  Laboratory  Univ.  of  Mich.,  2,  89; 
A.  B.  PRESCOTT,  1885:   "Control  Analyses  and  Limits  of  Recovery,"  Chem. 
News,  53,  78): 


Experiment. 

C.c.  strychnine  solution 
evaporated. 

Strychnine  sulphate  in 
grams. 

The  fading  purple. 

No   1  

5.0 

0.0000125 

Distinct. 

2 

40 

0.00001 

3    

30 

0.0000075 

<  « 

4  

2.0 

0.000005 

K 

5  

1.0 

0.0000025 

Good.  Play  of  colors 

6  

0.8 

0.000002 

less  marked. 
Faint. 

7  

0.6 

0.0000015 

Uncertain. 

The  solution  was  evaporated  in  a  common  evaporating-dish.    Doubtless 


STRYCHNINE.  453 

WORMLEY  '  obtained  very  satisfactory  evidence,  by  the  use  of 
the  dichromate,  from  0.0000013  gram  (0.00002  grain)  of  strych- 
nine ;  0.000007  gram  giving  evidence  as  satisfactory  as  could  be 
obtained  from  any  larger  quantity,  and  0.0000007  gram,  when 
deposited  within  a  narrow  compass,  giving  a  distinct  coloration. 
S.  J.  HINSDALE  (1885)  prefers  the  ceroso  eerie  oxide  as  an  oxi- 
dizing agent,  and  reports  a  good  play  of  colors  from  the 
0.0000007  gram  (0.00001  grain)  of  the  alkaloid.  It  is  to  be 
understood  that  the  limit  of  delicacy  of  the  color  test  is  wholly 
dependent  upon  the  concentration  of  the  alkaloid.  A  barely 
visible  fragment  of  crystal  of  strychnine  gives  a  good  play  of 
colors,  but  if  dissolved  in  a  few  c.c.  of  alcohol,  and  the  solution 
evaporated  in  a  common  dish,  the  residue  would  give  probably  a 
negative,  possibly  an  uncertain,  result.  These  statements  of  the 
smallest  quantity  of  pure  and  unmixed  alkaloid  capable  of  iden- 
tification give  no  answer  whatever  to  the  question  as  to  the 
smallest  quantity  of  the  poison,  existing  in  a  stomach  or  a  por- 
tion of  food  or  a  plant,  capable  of  recovery  and  identification. 
The  limits  of  recovery  receive  attention,  with  methods  of  Sepa- 
ration, under  0,  p.  461. 

Interferences  with  the  color  test  — (1)  Substances  diminishing 
the  delicacy  of  the  reaction.  Brucine  in  equal  quantity  with 
strychnine  prevents  the  coloration,  unless  the  quantity  of  each 
be  very  minute,  less  than  0.001  grain,  but  a  mixture  of  0  0001 
grain  of  each  gives  satisfactory  evidence  of  strychnine  (WORM- 
LEY).  "  The  0.01  grain  of  strychnine  with  0.001  grain  of  brucine 
yields  a  very  marked  reaction,  although  somewhat  masked " 
(Ibid.)  Morphine  is  nearly  as  influential  as  brucine  in  dimin- 
ishing or  preventing  the  color  test.  A  residue  from  a  solution 
of  0  01  grain  each  of  strychnine  and  morphine  gave  WORMLEY  2 
little  indication  of  the  presence  of  strychnine ;  but  a  similar  mix- 
ture of  0.001  grain  of  each  of  these  alkaloids  gave  good  evidence 
of  strychnine ;  while  even  a  minute  quantity  of  a  mixture  of 
three  parts  morphine  to  one  part  of  strychnine  gave  a  negative 
result. — The  absence  of  both  these  alkaloids,  therefore,  should  be 
assured,  if  need  be,  by  use  of  separative  solvents,  as  directed  un- 
der Separations  (e).  Of  inorganic  salts,  nitrates  and  chlorides 
have  been  named  as  diminishing  the  reaction.  Organic  matters 

had  the  residue  from  the  0.8  c.c.  of  No.  6,  or  even  that  from  the  0.6  c.c.  of  No.  7, 
been  brought  within  an  area  of  two  or  three  millimeters  diameter,  and  moist- 
ened with  much  less  than  a  drop  of  sulphuric  acid,  a  good  play  of  colors 
would  have  been  obtained  in  trials  6  and  7. 

1  "  Micro-chemistry  of  Poisons,"  1885,  p.  564. 

2 1860:  Chem.  News,  i,  243. 


454  STRYCHNOS  ALKALOIDS. 

acting  as  reducing  agents  undoubtedly  hinder  or  prevent  the 
reaction,  and  sugar  is  especially  influential  in  this  regard.  While 
it  is  the  rule  that  the  test  is  to  be  applied  in  the  absence  of  sub- 
stances not  alkaloids,  in  practice  it  is  sometimes  difficult  to  be 
certain  whether  these  matters  are  present  or  not.  This  question 
can  be  decided  by  a  control-test  as  follows :  Obtain  by  itself  a 
narrow  film  of  residue,  equal  to  that  tested  for  the  result  of 
analysis,  by  evaporation  of  a  little  of  the  recovered  solution  in  a 
porcelain  dish  by  itself.  Add  thereto  (aside  from  the  portions 
under  analysis)  say  1  c.c.  of  a  solution  containing  in  each  c.c. 
from  0.0000025  to  0.000005  gram  of  strychnine  sulphate  (p.  452), 
and  evaporate  again.  Or  evaporate  the  1  c.c.  with  the  small 
portion  of  solution  under  analysis.  This  residue,  with  the  added 
known  quantity  of  strychnine,  should  give  a  distinct  fading- blue 
coloration,  as  distinct  as  can  be  obtained  by  a  test  upon  a  residue 
from  1  c.c.  of  the  strychnine  solution  unmixed. — (2)  Substances 
giving,  in  part,  the  same  results  obtained  from  strychnine  in  the 
fading-purple  test,  and  presenting  the  so-called  "fallacies"  of 
this  test.  The  greater  number  of  these  substances  give  a  color 
with  sulphuric  acid  alone,  and  therefore  their  results  are  at  once 
excluded  from  all  indication  of  strychnine.  Among  these  sub- 
stances may  be  named  papaverine,  thebaine,  cryptopine,  ber- 
berine,  amygdalin,  veratrine,  and  cod-liver  oil.  Aloin  gives  a 
greenish  color,  fading  to  yellow.  Aniline,  colorless  with  sulphu- 
ric acid  alone,  on  adding  the  oxidizing  agent  presents  yellowish 
or  greenish  tints  slowly  deepening  to  blue,  which  deepens,  and 
(instead  of  fading)  finally  becomes  blue-black  to  black.  Gelse- 
mine,  colorless  alone  with  sulphuric  acid,  on  adding  dichromate 
or  other  oxidizing  agent  gives  a  reddish-purple  to  cherry-red 
color,  somewhat  resembling  that  of  strychnine.  Hydrastine,  but 
faintly  yellowish  with  sulphuric  acid,  on  adding  the  dichromate 
gives  red  to  green  color  (LYONS,  1886).  Curarine,  the  non-crys- 
tallizable  principle  of  worara,  obtained  from  botanical  sources 
allied  to  those  of  strychnine,  is  the  only  substance  besides  strych- 
nine which  has  been  found  to  give  the  threefold  result  of  the 
fading-purple  test  (WORMLEY). — The  use  of  the  permanganate, 
as  an  oxidizing  agent,  is  more  exposed  to  fallacy  than  the  other 
oxidizing  agents.  If  the  oxidizing  agent  be  mixed  witli  the  sul- 
phuric acid,  and  no  parallel  trial  be  made  with  sulphuric  acid 
alone,  the  reaction  of  cod  liver  oil  may  well  be  assumed  as  an 
indication  of  strychnine. 

The  physiological  test  is  to  be  placed  second  in  order  of  the 
value  of  evidence.  The  data  for  this  test  with  the  frog,  and  the 
limits  of  quantity  revealed  by  it,  are  given  under  b,  p.  449.  For 


STRYCHNINE.  455 

the  test  the  alkaloid  is  obtained  in  a  neutral  aqueous  solution 
of  a  salt,  as  the  sulphate. — The  taste  of  a  graded  dilute 
solution  gives  corroborative  proof  as  to  the  presence  and 
limit  of  quantity  of  strychnine  (5,  p.  448). — According  to 
WORMLEY,  a  grain  of  a  l-50000th  solution  of  the  alkaloid 
unmixed  with  other  matters  has  a  quite  perceptible  bitter 
taste ;  and  a  drop  of  a  l-10000th  solution,  even  in  mixture  with 
a  very  notable  quantity  of  foreign  matter,  usually  has  a  decided 
bitter  taste. 

Potassium  dichromate  solution,  added  to  solutions  of  strych- 
nine salts  not  very  dilute,  gives  a  crystalline  yellow  precipi- 
tate of  strychnine  dichromate,  (C21H22N2O2)2H2Cr2O7  (DrrzLEK, 
1886),  its  slow  formation  being  promoted  by  stirring.  The  crys- 
tals include  octahedra  and  often  bush-like  groups.  A  drop  of 
the  solution,  on  a  glass  slide,  may  be  treated  with  a  drop  of  the 
dilute  reagent,  the  mixture  stirred  with  a  fine  pointed  glass  rod, 
-and  from  time  to  time  examined  under  a  microscope  with  a  low 
power.  The  precipitate  is  not  soluble  in  excess  of  the  reagent 
or  in  quite  dilute  acids.  Solutions  of  strychnine  salts  in  1000 
parts  water  do  not  yield  an  immediate  precipitate,  but  from  this 
.and  much  more  dilute  solutions  crystals  can  be  obtained  as  di- 
rected above. 

The  general  reagents  for  alkaloids  give  precipitates  of  strych- 
nine. The  precipitate  with  Mayer's  solution,  potassium  mer- 
curic iodide,  appears  in  a  solution  of  a  salt  of  the  alkaloid  in 
150000  parts  of  water.  The  precipitate  by  phosphomolyb- 
date  dissolves  in  ammonia  without  coloration.  The  precipitate 
by  iodine  in  potassium  iodide  solution  is  obtained  in  very  di- 
lute aqueous  solutions  (1  :  100000),  reddish-brown,  and  soluble 
in  alcohol.  From  the  alcoholic  solution  somewhat  characteristic 
crystals  can  be  obtained.  Alkali  hydrates  give  crystallizable 
precipitates,  soluble  in  excess  only  in  the  instance  of  ammonia. 
The  ammoniacal  solution  gives  fine  crystals  of  the  free  alkaloid 
<«,  p.  448).  < 

Strychnine  is  noted,  among  alkaloids,  for  its  stability  under 
ordinary  influences  of  decomposition.  By  action  of  chlorine 
or  bromine,  monochlorstrychnine  or  bromstrychnine  is  readily 
formed,  as  a  substitution  compound :  by  action  of  iodine,  iodated 
hydriodides  are  formed,  as  addition  compounds.  By  treatment 
with  methyl  iodide,  the  salt  of  methyl-strychnine,  C21H21(CH3) 
N2O2.HI,  is  easily  obtained,  as  also  is  ethyl-strychnine  by  the 
same  means.  The  conversion  of  strychnine  into  brucine  remains 
under  investigation.  See  Constitution  of  strychnos  alkaloids, 
p.  446. 


456  STRYCHNOS  ALKALOIDS. 

e. — Separations. — Strychnine  may  be  concentrated  by  evapo- 
ration of  its  solutions  at  100°  C.,  without  loss  or  decomposition. — 
In  separation  by  solvents  immiscible  with  water,  chloroform  and 
benzene  take  it  up  most  abundantly  as  a  free  alkaloid  (from  al- 
kaline aqueous  solutions). — According  to  Dragendorff,  petroleum 
benzin,  though  dissolving  strychnine  but  very  sparingly,  may  be 
profitably  used  to  take  it  up  from  alkaline  solutions  as  a  means 
of  [qualitative]  separation  from  alkaloids  soluble  in  chloroform 
or  benzene  and  not  soluble  in  petroleum  benzin.1  From  acidu- 
lous solutions  strychnine  is  not  taken  by  any  of  the  ordinary  sol- 
vents immiscible  with  water  (except  as  traces  of  the  aqueous 
solution  itself  may  be  carried  in  solution  with  ether,  chloroform, 
and  amyl  alcohol). 

From  the  Nux-vomica,  in  total  alkaloids. — The  method  of 
Messrs.  DUNSTAN  and  SHORT,"  which  has  met  with  general  appro- 
val, is  as  follows :  Of  the  finely  powdered  nux-vomica  seeds  5 
grams  are  packed  in  the  percolator  of  a  continuous  extraction 
apparatus,  and  treated  actively  with  40  c.c.  •  of  alcoholic  chloro- 
form containing  25  per  cent,  of  alcohol,  until  exhausted,  which 
is  usually  accomplished  in  two  hours  or  less.  The  chloroformic 
solution  is  agitated  (in  a  separator)  with  25  c.c.  of  a  ten  per  cent, 
diluted  sulphuric  acid,  the  layer  of  chloroform  drawn  off  and 
shaken  again  with  15  c.c.  of  the  diluted  acid,  and  the  chloro- 
form layer  drawn  off.  The  formation  of  the  chloroform  layer  ie- 
much  facilitated  by  gently  warming  the  mixture.  The  mixed 
acid  solutions  should  be  quite  free  from  undissolved  chloroform, 
and  entirely  clear.  Chloroformic  turbidity  may  be  removed  by 
adding  a  little  chloroform  and  agitating  slowly  by  gradually  in- 
verting the  separator.  If  need  be,  the  mixed  acid  solutions- 
should  be  filtered,  through  a  filter  wet  with  the  dilute  acid,  and 
the  filter  washed  with  a  very  little  of  the  dilute  acid.  The  total 
acidulous  watery  solution  is  now  made  alkaline  with  ammonia, 
and  shaken  out,  in  the  separator,  with  25  c.c.  of  chloroform. 
The  clear  chloroformic  layer  is  slowly  drawn  off  into  a  weighed 
or  balanced  beaker.  If  not  readily  obtained  clear  by  subsiding, 
the  chloroformic  solution  may  be  run  through  a  small  double 
filter  wet  with  chloroform,  washing  the  filter  with  a  little  chloro- 
form. The  chloroform  is  gently  evaporated,  a  constant  weight 

1  Wormley  states  that  strychnine  requires  12500  parts  petroleum  benzin  for 
solution.  Even  if  this  hold  good  for  the  alkaloid  freshly  liberated,  it  still  would 
require  only  0.1  c.c.  of  the  solvent  to  carry  a  quantity  of  the  alkaloid  easily 
identified  by  the  color  test. 

2 1883:  Phar.  Jour.  Trans.  [3]  13,  665.  Given  here  with  very  slight  addi- 
tions in  details. 


STRYCHNINE.  457 

of  residue  is  obtained  at  100°  C.  or  on  the  water-bath,  for  which 
one  hour  is  usually  enough,  and  the  weight  of  residue  taken,  for 
the  quantity  of  total  alkaloids. 

From  preparations  of  Nux-vomica,  in  total  alkaloids.— 
DUNSTAN  and  SHOUT  present  directions  substantially  as  follows 
for  standardizing  an  alcoholic  percolate  of  nux-vomica  in  prepa- 
ration of  a  fluid  extract  of  uniform  alkaloidal  strength.1  The 
operation  may  be  applied  to  the  medicinal  tincture  or  fluid 
extract. 

Take  of  the  liquid  25  c.c.,  or  one  fluid-ounce,  or  other  suitable 
quantity  by  weight  or  volume,  according  to  the  purpose.  Eva- 
porate nearly  to  dryness  over  the  water-bath.  Treat  the  residue 
with  water  acidulated  with  sulphuric  acid,  in  the  proportion  of 
30  c.c.  of  a  7.5  per  cent,  sulphuric  acid  for  each  6  to  7  grams 
of  nux-vomica  represented  (1  f.  oz.  for  each  100  grains),  adding 
at  the  same  time,  for  same  quantities,  about  7  c.c.  (2  fluid  - 
drachms)  of  chloroform.  Agitate  and  warm  gently.  When  the 
chloroformic  layer  has  separated  draw  it  off,  add  to  the  aqueous 
liquid  ammonia  to  cause  an  alkaline  reaction,  and  agitate  with 
15  c.c.  (or  \  f.  oz.)  of  chloroform,  warming  as  before.  Draw  off 
the  chloroformic  solution  into  a  weighed  dish,  evaporate,  dry 
over  a  water-bath  for  one  hour,  cool,  and  weigh  for  total  alka- 
loids.— For  the  Solid  Extract  the  same  authors  dissolve  10  grains 
(or  0.6  gram)  in  J  f.  oz.  (15  c.c.)  of  water,  with  the  aid  of  heat,, 
add  60  grains  (4  grams)  of  sodium  carbonate  previously  dissolv- 
ed in  £  f.  oz.  (15  c.c.)  of  water,  and  agitate  with  £  f.  oz.  (15  c.c.) 
of  chloroform,  warming  to  obtain  a  separation.  The  chlorofor- 
mic solution  of  alkaloids  is  carefully  drawn  off,  and  agitated 
with  £  f.  oz.  each  of  diluted  sulphuric  acid  and  water  (or  30 
c.c.  of  5  to  7  per  cent,  sulphuric  acid).  The  clear  acidulous 
watery  solution  is  made  alkaline  by  adding  ammonia,  and  agi- 
tated with  £  f.  oz.  (15  c.c.)  of  chloroform.  When  the  liquids 
have  separated  the  chloroform  is  evaporated  off  in  a  weighed 
dish,  the  residue  dried  for  an  hour  over  the  water-bath  and 
weighed  as  total  alkaloids. — In  applying  this  process  to  the  resi- 
due from  (say  25  c.c.  of)  the  alcoholic  preparations,  Dr.  A.  B. 
LYONS  2  directs  to  shake  out  the  acidulous  liquid,  first,  with  two 
successive  portions  of  ether  (25  c.c.),  then  with  one  portion  of 
a  mixture  of  one  volume  of  chloroform  with  three  volumes 
of  ether,  the  shaking  not  to  be  too  violent.  The  aqueous* 
liquid  made  alkaline  is  extracted  by  the  same  ether-chloro- 

1 1884:  Phar.  Jour.  Trans.  [3]  13. 

'1885:  Proc.  Mich.  State  P/iar.  Asso.,  2,  183. 


458  STRYCHNOS  ALKALOIDS. 

form  mixture,  applying  it  in  two  successive  portions  (30  and 
20  c.c.) 

Separation  of  Strychnine  from  Brucine.  -  (1)  By  dilute  al- 
cohol of  sp.  gr.  0.970  (about  21$  weight,  26$  vol.)  In  1878 ' 
the  author  communicated  results  as  follows :  Solution  requires 

For  strychnine,  2617  parts  of  21$  (weight)  alcohol,  500  parts  of 

39$  alcohol. 
For  brucine,  38  parts   of  21$    (weight)    alcohol,    22    parts   of 

39$  alcohol. 

When  one  part  each  of  strychnine  and  brucine  were  digested 
one  hour  at  ordinary  temperature  with  100  parts  of  alcohol  of 
sp.  gr.  0.970,  filtered,  and  the  undissolved  alkaloid  washed  with 
100  parts  of  the  same  alcohol,  the  residue  of  strychnine  gave  no 
qualitative  test  for  brucine,  but  the  brucine  left  on  evaporating 
the  filtrate  gave  a  slight  color  test  for  strychnine  (even  in  pre- 
sence of  the  excess  of  the  brucine). 

(2)  By  precipitation  with  ferrocyanifJe  (DUNSTAN  and 
SHORT,  1883).  The  sulphates  of  the  alkaloids  in  aqueous  solu- 
tion acidified  with  sulphuric  acid  are  precipitated  with  potas- 
sium ferrocyanide.  The  strychnine  is  entirely  precipitated,  both 
when  alone  and  when  in  the  presence -of  brucine,  while  the  hm- 
cine  is  not  precipitated  unless  in  concentrated  solution.  ScHWEit- 
tsiNGEE  (1885)  did  not  obtain  good  results  by  this  method. 

Separation  from.'  Tissues  and  Foods  in  analysis  for  poi- 
sons.— A  weighed  quantity  (one  part)  of  the  material  is  placed 
in  an  evaporating-dish  or  wide  beaker,  finely  divided  under 
the  points  of  a  pair  of  sharp,  bright  shears,  with  moistening  if 
need  be  to  bring  to  a  soft  and  homogeneous  pulp,  about  an  equal 
quantity  of  wrater  containing  about  one  per  cent,  of  sulphuric 
acid  is  added,  and  the  mass  digested,  with  stirring,  on  the  water- 
bath  for  15  minutes.  Four  or  five  parts  of  well-rectified  90$  al- 
cohol are  added,  and  the  whole  digested,  with  frequent  stirring, 
at  a  little  below  the  boiling  temperature  of  the  alcohol,  for  about 
an  hour.  The  edges  are  to  be  kept  free  from  dried  residue.  It 
is  then  cooled  and  strained  through  close  muslin,  or  filtered 
through  open  filter-paper  by  the  help  of  a  filter-pump.  The 
residue  is  digested,  successively,  with  two  smaller  portions  of 
alcohol,  keeping  the  reaction  of  the  mass  constantly  acid,  the 
filtrates  from  all  being  received  together  in  a  wide  mouthed  flask, 
and  the  strainers  or  filters  well  washed  with  the  alcohol.  The 
filtered  liquids  are  concentrated  to  a  syrupy  consistence,  with 

1  Pro.  Am.  Pharm.,  26,  806;   Year-book  of  Phar.,  1879,  97. 


STRYCHNINE.  459 

occasional  gentle  rotation  of  the  flask,  preventing  dried  residues 
on  the  edges.  Four  or  live  parts  of  absolute  or  nearly  abso- 
lute alcohol  are  added,  the  mixture  shaken  by  rotating  the 
flask,  and,  when  cold,  filtered  into  another  flask,  arid  the  filter 
well  washed  with  the  absolute  alcohol.  The  entire  filtrate  is 
evaporated  on  the  water-bath  to  remove  all  the  alcohol,  when 
about  two  parts  of  water  are  added.  If  the  reaction  be  not 
sharply  acid  to  litmus,  it  is  made  so  by  adding  a  drop  or  two 
of  diluted  sulphuric  acid.  The  mixture  is  filtered,  and  the  resi- 
due and  filter  well  washed  with  small  portions  of  water,  re- 
ceiving the  entire  filtrate  in  a  small  separator,  or  strong  tube 
having  a  good  cork.  It  is  now  shaken  out  with  chloroform,  in 
one  or  more  portions,  or  as  long  as  this  solvent  continues  to  ex- 
tract anything.  The  clear  chloroform  layer  is  drawn  off  by  the 
separator,  or  forced  out  of  the  tube  as  water  is  delivered  from  a 
wash-bottle,  the  tubulated  stopper  fitted  for  that  purpose  having 
an  adjustable  delivery  tube  brought  to  the  conical  bottom  of  the 
container.  The  chloroform  solution  is  washed  once  or  twice 
with  a  little  faintly  acidulous  water,  and  the  washings  added  to 
the  aqueous  liquid.  The  chloroform  solution  is  reserved  for  any 
tests  desired.  The  aqueous  solution  is  made  distinctly  alkalin^ 
by  adding  ammonia,  and  exhausted  by  shaking  out  with  from 
three  to  five  portions  of  the  chloroform.  The  united  chloro- 
formic  liquids  are  to  be  obtained  perfectly  clear.  A  zone  of  par- 
tial emulsion  next  to  a  supernatent  watery  layer  may  be  resolved 
by  introducing  into  the  zone  a  c.c.  or  so  each  of  fresh  chloro- 
form and  of  water,  and  tapping  the  separator.  If  need  be,  the 
chloroform  so  added  may  be  made  slightly  alcoholic.  Also,  a 
little  portion  of  emulsified  chloroform  may  be  washed  with  chlo- 
roform on  a  filter  wet  with  the  same  solvent.  Now  an  aliquot 
part  of  the  total  chloroformic  solution  (from  the  alkaline  liquid) 
may  be  evaporated  for  preliminary  tests.  The  residue  so  ob- 
tained is  usually  colored  and  loaded  with  substances  not  alka- 
loids. When  no  other  alkaloid  than  strychnine  is  sought,  the 
residue  from  evaporation  of  the  (remaining)  chloroform  solution 
may  be  purified  as  follows :  The  residue  is  treated  with  concen- 
trated sulphuric  acid,  one  or  two  drops,  or  only  enough  to 
moisten  the  whole,  covered  and  heated  on  the  water-bath,  or, 
better,  heated  in  an  oven  at  100°  C.,  avoiding  any  higher  tempe- 
rature, for  an  hour  or  so.  To  the  carbonized  mass,  when  cold, 
barium  carbonate  is  added,  to  neutralize  nearly  all  the  acid,  still 
leaving  an  acid  reaction.  The  little  mass  is  now  exhausted  with 
small  portions  of  water,  and  the  solution  and  washings  filtered 
into  a  small  separator.  The  aqueous  solution  is  now  made  alka- 


460  STRYCHNOS  ALKALOIDS. 

line  by  adding  ammonia,  and  exhausted  by  repeatedly  shaking 
out  with  chloroform  in  small  portions.  The  entire  chloroform 
solution  is  received  in  a  graduated  cylinder,  and  aliquot  parts  are 
evaporated  in  small  porcelain  and  glass  dishes,  for  the  several 
tests,  and  for  trial  as  to  qualitative  limits,  also,  if  desired,  for 
volumetric  estimation.  The  residues  will  contain  some  ammo- 
nium sulphate,  the  crystals  of  which  are  likely  to  be  seen  in  mi- 
croscopic examinations.  To  obtain  a  portion  free  from  ammo- 
nium salts  and  from  sulphates  in  general,  treat  one  of  the  residues 
with  water  and  barium  carbonate,  evaporate  to  dryness,  take  up 
with  warm  alcohol,  filter,  and  evaporate  the  alcoholic  solution, 
for  another  residue. 

Strychnine  may  be  separated  from  the  Urine  by  evaporat- 
ing the  acidulated  liquid  to  a  syrup,  stirring  with  strong  or  abso- 
lute alcohol,  filtering  and  washing  well  with  the  same  alcohol, 
concentrating  the  filtrate  to  a  syrup,  which  is  dissolved  in  water 
enough  to  make  a  limpid  solution.  This  is  washed  (while  aci- 
dulous) with  chloroform  ;  then  made  alkaline  by  adding  ammo- 
nia, and  washed  with  one  or  more  portions  of  chloroform.  The 
chloroformic  solution  is  evaporated,  either  all  together  or  in 
aliquot  portions,  for  direct  tests  upon  the  residue  or  for  further 
purification,  as  directed  on  p.  459.  As  to  the  occurrence  of 
strychnine  in  the  urine,  following  administration,  results  are 
stated  under  5,  p.  449. 

Recovery  from  Alcoholic  Beverages. — Messrs.  GRAHAM  and 
HOFMANN,  in  1852,  made  extensive  analyses  of  the  ales  and 
beers  of  Great  Britain  for  strychnine,  as  follows :  Half  a  gallon 
of  the  ale  was  shaken  with  2  oz.  of  animal  charcoal,  and,  after 
standing  12  to  24  hours,  filtered  through  paper.  The  drained 
charcoal  was  boiled  half  an  hour  in  purified  alcohol,  and  the  fil- 
tered alcohol  distilled  off.  The  watery  residue  was  made  alka- 
line with  potassa,  and  agitated  with  an  ounce  of  ether  [chloro 
form].  The  residue  from  evaporation  of  the  ether  was  tested. 
Taking  -|  grain  of  the  alkaloid  in  J  gallon  of  the  malt  liquor,  the 
operators  invariably  obtained  the  color  test  in  the  final  residue.— 
Probably  a  preferable  procedure  would  be  the  treatment  directed 
above  for  separation  from  the  urine. — With  distilled  spirits,  such 
as  whisky,  the  same  operation  (last  referred  to)  is  advisory,  the 
alcohol  being  first  distilled  off,  when  the  slight  quantity  of  resi- 
due usually  renders  the  operation  a  very  simple  one. — Single 
cases  of  the  detection  of  strychnine  in  beer  in  Eastern  Europe 
have  been  reported.  There  is  no  evidence,  and  no  probability, 
that  strychnine  has  ever  been  used  in  the  sophistications  of  dis- 
tilled spirits. 


STRYCHNINE. 


461 


Limits  of  Recovery  from  complex  orgdnic  matter. — From 
the  experiments  of  Mr.  Kirchmaier,  with  the  author's  co-opera- 
tion,1 it  appeared  that  the  limits  of  analytical  separation,  by  a 
process  essentially  the  same  as  that  just  detailed,  were  as  follows  : 
With  50  grams  of  meat,  the  loss  of  strychnine  was  for  one  part 
of  meat,  0.00000795  part  of  strychnine ;  or  for  one  part  of  the 
alkaloid,  125786  parts  of  the  tissue-material.2  That  is  to  say,  in 
separating  strychnine  from  an  avoirdupois  pound  of  tissues  the 
loss  of  alkaloid  is  from  one  thousand  to  two  thousand  times  the 
least  quantity  needed  for  certain  identification  (p.  452). 

The  deposition  of  strychnine  in  various  organs  of  the  living 
body  receives  statement  under  &,  at  p.  450.  It  is  capable  of 
recovery  from  partly  decomposed  organs  some  time  after  death, 
subject  to  limitations  not  yet  very  definitely  established.  No 
other  alkaloidal  poison  resists  destruction  in  the  interred  body  any 
better  than  strychnine,  probably  none  other  resists  as  well.  Yet 
it  is  by  no  means  indestructible  when  contained  in  putrefactive 
tissue.  The  data  obtained  by  adding  strychnine  to  tissues,  and 
recovering  it  after  some  months  of  putrefactive  decomposition, 
are  but  imperfectly  applicable  to  cases  of  poisoning  by  the  al- 
kaloid, because  of  the  attenuation  that  results  from  absorption 
and  elimination.  Wormley  states 3  that  "  the  longest  period  in 
which  the  analysis  furnished  positive  evidence  of  its  presence 
in  the  exhumed  human  body  is  43  days  after  death  (Ann.  d?Hyg., 
1881,  359)."  But  in  the  case  of  Magoon,  in  New  Hampshire, 
1875,  Drs.  Hayes  and  E.  S.  Wood,  of  Boston,  found  strychnine 
in  the  body  of  a  woman  advanced  in  years,  exhumed  one  year 
and  three  days  after  death;  and  the  analysts  reported  0.15  grain 
in  the  stomach,  0.23  grain  in  the  liver,  and  presence  of  the  alka- 
loid in  the  intestines.  Death  had  occurred  in  less  than  an 
hour  after  administration  of  an  unknown  quantity  of  the  poi- 

1  "Control  Analyses  and  Limits  of  Recovery  in  Chemical  Separations,'1 
1885:  Chem.  News,  53,  78.  Contributions  from  the  Ghem.  Lab.,  Univ.  of  Mich., 
2,91. 


2  Experiment   4,     5  grams  meat,    0.00016    strychnine,  good  color-test. 

5, 

0.00012 

faint 

6, 

0.00008 

very  faint 

7, 

0.000064 

negative 

*          8,    5 

0 

0.0004 

good 

9, 

0.0002 

faint 

'        10, 

0.00016 

negative 

3, 

br 

ad,  0.0001 

good 

4, 

0.0008 

faint 

5, 

0.0006 

very  faint 

r 

*  rt  1     _   T 

'••         6, 

__      ^ 

0.0004 

negative 

•'*  \ 

32ded.  "  Micro-Chem.  Poisons,"  1885. 


462  STRYCHNOS  ALKALOIDS. 

son,  in  a  tumbler  of  hot  liquid  of  extreme  bitterness.  In  1875 
Prof.  WORMLEY  made  analysis  of  the  stomach  and  liver  seven 
months  after  death,  and  the  chemical  tests  gave  no  evidence  of 
strychnine,  although  the  final  residues  had  a  bitter  taste.  Death 
had  occurred  within  two  hours,  and  the  symptoms  and  other 
proofs  were  such  that  there  was  a  conviction  for  poisoning  (Ohio 
v.  Dresbach,  1881).  Buchner,  Gorup-Besanez,  Wislicenus,  and 
Eanke  (1881)  made  a  series  of  experiments  upon  seventeen  dogs, 
killed,  each,  by  0.1  gram  of  strychnine,  and  buried  from  100  to 
330  days  before  analysis.  In  no  case  did  the  chemical  tests  show 
the  presence  of  strychnine,  though  the  physiological  test,  with 
frogs,  obtained  tetanic  convulsions,  and  the  residues  had  a  bitter 
taste. 

f. — Quantitative. — Strychnine  is  estimated  gravimetrically 
by  weight  of  the  anhydrous  alkaloid,  dried  at  100°  C.  A  volu- 
metric estimation  (less  exact  than  the  gravimetric)  is  obtained 
by  Mayer's  solution,  each  c.c.  of  which  represents  0.0167  gram 
of  strychnine  (^^^^  of  334,  in  grams).  The  end  of  the  reaction 
is  distinct,  and  the  precipitate  settles  fairly  well  in  acidulated 
water,  but  settles  better  in  a  concentrated  solution  of  potassium 
chloride  (DRAGENDORFF,  1874),  when  each  c.c.  of  the  entire  solu- 
tion dissolves  0.00216  gram  of  the  precipitate  (ibid.)  The 
composition  of  the  precipitate  as  C^H^KgO^HIHglo  was  near- 
ly sustained  by  the  determinations  of  mercury  and  of  iodine 
communicated  by  the  author  in  1880.1  This  chemical  formula 
corresponds  to  36.47$  strychnine  in  the  precipitate.  Dragendorff 
gives  a  gravimetric  trial  by  washing,  drying,  and  weighing  the 
precipitate,  whereby  there  was  a  loss  of  only  1.8$  on  the  basis  of 
this  formula.  Though  more  constant  than  the  greater  number  of 
alkaloidal  iodomercurates,  the  precipitate  is  not  the  most  favora- 
ble form  for  gravimetric  purposes.  And  in  the  volumetric  de- 
termination the  solution  is  to  be  made  of  200  parts  to  1  of  the 
alkaloid. 

g. — Tests  for  Impurities. — "  Strychnine  should  not  be  red- 
dened at  all,  or  at  most  but  very  faintly,  by  nitric  acid  (absence 
of  more  than  traces  of  brucine)."  May  be  colored  yellowish  but 
not  red  when  rubbed  with  nitric  acid  (Ph.  Germ.)  Not  colored 
by  nitric  acid  (Br.  Ph.) — A  more  strict  exclusion  of  brucine  is 
effected  by  washing  the  free  alkaloid  with  dilute  alcohol  (sp.  gr. 
0.970)  to  separate  the  brucine,  as  described  on  p.  458,  the  residue 

1  CHEM.  LAB.  UNIV.  MICH.:  Am.  Chem.  Jour.,  2,  297-99;  Jour.  Chem.  Soc. 
42,  664. 


BRUCINE.  463 

from  evaporation  of  the  filtered  dilute  alcohol  being  tested  with 
nitric  acid.1  Of  ten  samples  of  commercial  strychnine,  treated 
in  this  way,  all  but  two  gave  tests  for  brucine. 

BRUCINE,  C23H26]SroO4  =  394.  Crystallizes  with  4H2O, 
15.45$. — For  constitution  of  the  alkaloid  see  p.  446  ;  yield  in 
nux-vomica,  p.  447. 

Brucine  is  identified  by  its  color-tests  with  nitric  acid  and 
other  additions,  its  dichromate  precipitate,  its  crystalline  forms, 
and,  its  physiological  effects  as  a  convulsent  (d).  It  is  distin- 
guished from  strychnine  by  a  negative  result  in  the  "  fading- 
purple  "  test,  and  the  positive  reactions  with  nitric  acid,  etc.  (d). 
It  is  separated  with  strychnine,  and  from  strychnine,  as  de- 
scribed on  pages  456,  460 ;  and  is  estimated  gravimetrically  or 
volumetrically  (/")• 

a. — Transparent  or  colorless,  oblique,  four-sided  crystals,  or 
in  groups  of  delicate  needles,  varied  in  form  according  to  the 
solvent  and  the  conditions.  The  crystals  effloresce  in  dry  air, 
and  on  the  water-bath  the  alkaloid  soon  becomes  anhydrous.  It 
melts  at  151°  C.  (BLYTH,  1878),  at  115.5°  C.  [when  anhydrous?] 
(Gur).  It  gives  a  decomposition-sublimate  in  the  "  subliming 
cell"  at  150°  C.  and  above  (BLYTH),  at  204°  C.  (Guy). 

~b. — Brucine  is  extremely  bitter.  In  effects  in  general  it  re- 
sembles strychnine,  but  a  far  greater  quantity  is  required  for  the 
same  effect  T.  L.  BKUNTON  (1885)  found  that  it  is  excreted  far 
more  rapidly  than  strychnine,  so  rapidly  that  when  given  by  the 
stomach  to  animals  pure  brucine  has  little  effect.  Given  hypo- 
dermically  it  causes  death  by  convulsent  action.  WOKMLEY 
states  that  the  effect  of  brucine  is  that  of  strychnine,  with  T^  the 
intensity. 

c. — Effloresced  brucine  dissolves  in  850  parts  cold  or  500 
parts  boiling  water,  the  crystals  being  considerably  more  soluble. 
Very  soluble  in  alcohol,  absolute  or  aqueous.  As  to  its  solubility 
in  certain  strengths  of  dilute  alcohol,  see  page  458.  Almost 
insoluble  in  ether,  soluble  in  chloroform,  benzene,  or  amyl 
alcohol. — The  ordinary  salts  of  brucine  are  soluble  in  water  and 
in  alcohol,  not  in  ether. 

d. — Nitric  acid  gives  a  red  color  with  brucine.  For  the 
proper  intensity  the  acid  should  be  concentrated,  near  1.42  spe- 
cific gravity,  and  the  alkaloid  should  be  dry  and  placed  over  a 

1  The  author  and  A.  D.  Smith,  1878:  Proc.  Am.  Pharm.,  26,  807. 


464  STRYCHNOS  ALKALOIDS. 

white  ground.  If  the  alkaloid  be  concentrated  at  one  point,  and 
minute  in  quantity,  it  may  be  treated  with  less  than  a  drop  of 
the  acid,  added  at  the  point  of  a  sharp  glass  rod.  On  standing, 
or  heating,  the  color  changes  to  yellowish  ;  on  evaporating  to 
dryness  the  red  color  returns  in  the  residue.  About  0.0000013 
gram  (0.0000-2  grain)  is  the  limit  of  quantity  for  distinct  colora- 
tion, with  the  best  concentration. — Sulphuric  acid  alone  applied 
to  the  dry  alkaloid  causes  a  faint  rose  color.  If  in  a  drop  of  the 
rose  solution  of  the  concentrated  acid  a  minute  fragment  of  po- 
tassium nitrate  be  placed,  an  orange-red  color  is  obtained.  If 
the  concentration  be  of  the  best,  about  the  0.00003  gram  is  suf- 
ficient for  a  sensible  reaction. — If  the  dry  alkaloid  or  its  salt  be 
treated  with  a  drop  or  just  wet  with  nitric  acid,  as  above  direct- 
ed, warmed  till  the  color  turns  to  the  yellow,  then  cooled  and 
touched  with  a  drop  or  less  of  good  solution  of  stannous  chlo- 
ride, a  purple  to  violet  color  is  obtained.  Excess  of  either  the 
nitric  acid  or  the  tin  salt  is  to  be  avoided.  The  heating  is  only 
necessary  to  bring  out  the  full  delicacy  of  the  reaction.  Sodium 
sulphide  solution  (by  saturating  caustic  soda  solution  with  H2S) 
may  be  used  instead  of  stannous  chloride.  The  reaction  with 
tin  salt  may  be  recognized  with  the  0.00001  gram  of  the  alkaloid. 
Of  the  three  allied  color-tests  just  described,  the  last  is  the  most 
characteristic,  and  the  agreement  of  the  three  furnishes  quite 
conclusive  proof  of  identity,  with  distinctions  from  morphine, 
narcotine,  and  other  alkaloids. — In  the  sulphuric  acid  and  di- 
chromate  test  made  for  strychnine,  brucine  slowly  reduces  the 
chromic  acid,  with  colors  changing  from  dull  orange  to  greenish, 
without  the  least  resemblance  to  the  "  fading  purple."  Froehde's 
reagent  gives  a  red  to  yellow  color.  A  solution  of  brucine 
in  dilute  sulphuric  acid,  touched  with  very  dilute  dichromate 
solution,  gives  a  red  color  changing  to  duller  tints.  Mer- 
curous  nitrate  (free  from  excess  of  nitric  acid)  gives  a  re- 
action somewhat  like  that  of  nitric  acid,  but  developed  only  on 
heating,  the  color  being  carmine,  and  permanent  on  evaporating 
to  dryness. 

Solution  of  a  brucine  salt,  with  solution  of  potassium  dichro- 
mate, yields  a  yellow  crystalline  precipitate  of  brucine  chromate, 
in  groups  of  bent  needles,  formed  in  quite  dilute  solutions,  and 
somewhat  characteristic.  The  precipitate  dissolves  in  nitric  acid 
with  a  red  color. 

The  general  reagents  for  alkaloids  give  the  customary  preci- 
pitates with  brucine.  Very  dilute  solutions  give  the  precipitate 
with  iodine  in  potassium  iodide  solution.  The  precipitate  form- 
ed by  phosphomolybdate  is  of  an  orange  tint,  dissolving  in  am- 


TANNINS.  465 

inonia  to  a  yellow-green  solution.  The  caustic  alkalies  cause 
a  precipitate,  gradually  becoming  crystalline,  and  somewhat  sol- 
uble in  ammonia. 

The  physiological  test  of  brucine,  with  the  frog,  is  qualita- 
tively nearly  the  same  as  that  for  strychnine  (pp.  454,  449),  but 
a  very  much  larger  quantity  of  brucine  is  required  for  the  same 
effect. 

e. — Separations. — Brucine  may  be  obtained  from  an  aqueous 
or  other  solution  by  evaporation  at  100°  C.,  without  loss. — The 
aqueous  solution  of  its  salts  may  be  washed  with  any  of  the 
ordinary  solvents  immiscible  with  water,  its  salts  not  being  solu- 
ble in  these  solvents.  On  making  the  aqueous  liquid  alkaline, 
chloroform  or  benzene  serves  well  as  a  solvent,  and  amyl  alco- 
hol also  takes  it  up.  Petroleum  benzin  dissolves  it  to  some 
extent. 

The  separation  of  brucine  with  strychnine,  from  nux-vomica 
and  from  its  preparations,  is  described  under  Strychnine,  p.  456. 
The  separation  from  strychnine  is  given  at  p.  458.  In  analysis 
for  poisons,  brucine  will  be  obtained  with  strychnine  by  the 
methods  detailed  at  pages  458,  460. 

f. — Quantitative. — Brucine  is  estimated  gravimetrically  in 
the  same  manner  as  strychnine  (p.  462),  the  residue  of  free  al- 
kaloid being  dried  at  100°  C.  to  a  constant  weight,  when  it  can 
be  weighed  as  anhydrous  — In  the  volumetric  method  with  May- 
er's solution,  Mayer's  factor  for  1  c.c.  of  the  solution  was  0.0233 
gram  of  the  alkaloid. 

SULPHOCARBOLIC  ACID.     See  PHENOL,  p.  405. 

TANNINS. — Tannic  Acids.  Gerbsauren.  --  Vegetable 
educts  of  an  astringent  taste,  amorphous  or  obscurely  crystal- 
line solids,  not  volatile  without  change,  of  very  slight  acid  power, 
and  freely  soluble  in  water  and  in  alcohol.  They  give  blue  or 
green  precipitates  with  ferric  salts,  and  thick  precipitates  with 
gelatin,  albumen,  and  starch  paste.  In  most  cases  they  pre- 
cipitate the  alkaloids,  likewise  tartrate  of  antimony  and  potas- 
sium, and  are  dissolved  but  sparingly  by  dilute  mineral  acids. 
They  are  all  strong  reducing  agents,  giving  reductions  with 
Fehling's  solution,  with  permanganate,  and  with  salts  of  silver 
and  of  gold.  The  greater  number  of  them  convert  animal  mem- 
brane into  leather.  They  are  darkened  and  decomposed  by  al- 
kali hydrates.  In  solutions  they  are  instable. 

There  are  many  diversities  of  character  and  composition   of 


466 


TANNINS. 


The  best  known  of  these  differences  may  be  stated  as 


tannins, 
follows : 

(1)  Gluooside-tannins.      When 
boiled  with  dilute   mineral 
acids,  yield  (a)  a  crystalliza- 
ble  acid    or  its  anhydride, 
or  (b)  a  phlobaphene  (a  re- 
sin-like  body),   along   with 
a  glucose.1 

(2)  Iron-bluing  tannins.     With 
ferric    salts    give    blue    to 
black  precipitates  or  colors. 
The  ferroso-ferric  solutions, 
slightly  basic,  give  the  best 
reactions.       Mineral     acids 
dissolve  and  decolor. 

(3)  Tannins  not  tanning  agents. 
Do   not   form    leather,  nor 
preserve  animal  membrane, 
though    precipitating   solu- 
tions of  gelatin  (WAGNER  3). 

(4)  Tannins  which,  in   sublim- 
ing, or  in  fusing  with  po- 
tassium   hydrate,    yield    a 
trihydroxybenzene,   *     C6H3 


(1)  Tannins  not  glucosides. 


For  determination  whether 
a  glucoside  or  not,  see  be- 
low. 

(2)  Iron  -  greening        tannins.* 
With     ferric    (basic)    salts 
give    greenish    precipitates 
or    colors.      Brown    colors 
sometimes  obtained.     Tints 
varied  by  conditions. 

(3)  Tanning  materials.  Change 
animal  membrane  into  leath- 
er,  not   putrescible.      Also 
precipitate  solutions  of  gela- 
tin. 

(4)  Tannins  which,  in   sublim- 
ing, yield  a  dihydroxy phe- 
nol,   C6H4(OH)2,    and,  on 
fusing  with  potash,  yield  an 


1  "  I  have  arrived  at  the  curious  result  that  tannic  acid,  when  acted  upon 
by  acids,  yields,  together  with  gallic  acid,  sugar,  so  that  henceforth  tannic  acid 
maybe  classed  with  the  conjugate  sugar  compounds." — STRECKER  in  a  letter 
to  Hofmann  in  1853.    In  1872  SCHIFF  found  the  product  to  be  primarily  digallic 
instead  of  gallic  acid. 

2  Of  the  iron-greening  tannins  examined  only  willow-tannin  was  found  to 
be  a  glucoside.— STENHOUSE,  1861.     "  Tannins  in  the  green  parts  of  plants,  ac- 
cording to  their  nature,  affect  iron  solutions  differently ;  that  which  colors  iron 
green  is  apparently  an  oxidation  product  of  that  which  colors  iron  blue,  and 
the  author  thinks  that  the  latter,  under  the  influence  of  transpiration,  breaks 
up  into  the  former  modification  and  sugar/' — E.  JOHANSON,  1879:  Jour.  Chem. 
Soc.,  26,  161,  from  Arch.  Pharm.  [3]  13,  103-130.     Regarding  iron  colors  with 
phenol  hydroxyl,  see  SCHIFF  as  quoted  under  Carbolic  Acid,  in  reaction  with 
Ferric  Chloride,  p.  399. 

3  Zeitsch.  analyt.  Chem.,  5,  1.     Wagner  states  that  the  pathological  tan- 
nins of  the  galls  of  species  of  Quercus  and  Rhus  do  not  form  true  leather  or 
preserve  animal  membrane  from   putrefaction.      LOWENTHAL   (1877:   Zeitsch. 
anal.  Chem,^l6,  47)  found  that  precipitates  of  gelatin  with  gallotannin  and 
sumach-tannin,  standing  under  water  for  two  years,  still  gave  no  odor  of  putre- 
faction. 


TANNINS.  467 

(OH)3,  such  as  Pyrogallol  acid,  as  Protocatechuic  acid. 

(HLASIWETZ).  C6H3(OH)2CO2H     (HLASI- 

WETZ). 

(5)  Pathological  tannins.  (5)  Physiological  tannins. 
Formed  in  punctured  vege-  From  uninjured    vegetable 
table  tissues.     Gallotanmns  tissues  (Wagner).     Include 
(WAGNER,  1866  ').     Includ-  various  glucosides  and  iron- 
ing   sumach-tannin   (STEN-  bluing  tannins. 
HOUSE,  1861). 

In  testing  for  glucoside  tannins,  the  solution,  not  very  di- 
lute, is  iirst  tried  as  to  its  deportment  with  ferroso-ferric  solution, 
gelatin  solution,  cinchona  sulphate  solution,  and  Fehling's  solu- 
tion. Sulphuric  acid  equal  to  one  or  two  per  cent,  is  now  added 
to  a  portion,  and  the  liquid  is  boiled  for  an  hour  or  two  Or 
hydrochloric  acid  is  added,  to  give  about  the  same  percentage 
of  real  acid,  the  liquid  sealed  up  in  glass  tubes  and  heated  at 
100°  C.  for  an  hour  or  longer.  A  portion  of  the  liquid  is  now 
dropped  into  cold  water,  to  see  whether  sparingly  soluble  fer- 
mentation products  may  precipitate,  so  that  they  can  be  re- 
moved by  filtration.  Otherwise  the  liquid  may  be  shaken  with 
successive  portions  of  ether,  or  chloroform,  or  acetic  ether 
(DRAGENDORFF).  The  liquid  is  now  nearly  or  quite  neutralized 
by  the  addition  of  fixed  alkali  hydrate,  and  tested,  as  at  first, 
with  ferroso-ferric  solution,  gelatin  solution,  cinchona  sulphate 
solution,  and  Fehling's  solution,  noting  if  these  results  differ 
from  those  obtained  before  boiling.  The  production  of  glu- 
coses may  be  further  investigated,  by  a  fermentation  test,  with 
yeast  (see  under  Sugars),  and  by  optical  examination  as  to  rota- 
tory power. 

Tannins  are  precipitated  by  lead  acetate,  copper  acetate,  and 
zinc  ammonio  chloride,  and  by  the  salts  of  nearly  all  the  non 
alkali  metals.  The  removal  of  tannins  from  solutions  may  be 
effected  by  digesting  the  liquid  with  recent  ferric  hydrate,  zinc 
oxide,  copper  oxide,  or  lead  oxide,  and  filtration.  Also  by 
maceration  with  animal  membrane  or  rasped  hide ;  or  by  filtra- 
tion through  purified  animal  charcoal.  Gelatin  gives  better 
precipitates  in  solution  saturated  with  ammonium  chloride  or 
sodium  chloride,  and  the  addition  of  sulphuric  or  hydrochloric 
acid  further  helps  the  separation  of  the  precipitates.  Separa- 
tions by  acetic  ether,  and  non -precipitation,  are  given  under 
Gallotannin. 

1  See  note  on  p.  466. 


468  TANNINS. 

ESTIMATION  OF  TANNINS  and  Valuation  of  Tanning  Mater- 
ials.  (1)  Method  of  LOWENTHAL.'  Titration  by  a  perman- 
ganate solution,  before  and  after  removal  of  the  tannin  by 
gelatin  in  solution  saturated  with  sodium  chloride  and  acidi- 
fied. Both  titrations  made  in  presence  of  much  indigo  solution, 
which  regulates  the  oxidation  and  serves  as  an  indicator.  The 
method  employs  the  following-named  solutions :  (a)  Permanga- 
nate of  potassium  solution  :  1.333  or  (Kathreiner)  1.000  gram  of 
the  crystallized  salt  to  1  liter.  (J)  Indigo  solution:  6  grams 
pure  precipitated  indigo,  and  50  c.c.  concentrated  sulphuric  acid, 
per  liter.  There  should  be  added  sufficient  of  the  indigo  to  re- 
quire for  itself  two-thirds  of  all  the  permanganate  used  (Kathrei- 
ner). (c)  The  solution  of  Glue  and  common  salt  is  made  by 
macerating  25  grams  of  good  transparent  glue  in  cold  water, 
then  heating  to  dissolve,  making  up  to  1  liter,  and  saturating 
with  good  common  salt.  It  should  be  filtered  clear  when  used. 
(d)  The  acidulated  solution  of  Common  Salt  is  a  saturated  solu- 
tion with  addition  of  25  c.c.  of  sulphuric  acid  in  a  liter. — In  the 
analysis  20  to  25  grams  of  bark,  or  10  grams  of  sumach  or 
valonia,  are  boiled  with  portions  of  water  until  fully  exhausted, 
and  the  solution,  when  cold,  made  up  to  1  liter.  Of  this  10  c.c. 
are  diluted  to  800  or  1000  c.c.,  25  c.c.  of  the  indigo  and  acid 
solution  are  added,  the  mixture  treated  with  the  permanganate 
solution,  drop  by  drop  from  the  burette,  with  constant  stirring, 
until  the  blue  color  changes  to  a  clear  yellow,  showing  no  green 
tint,  and  the  number  of  c.c.  of  permanganate  is  noted.  Another 
25  c.c.  of  the  indigo  and  acid  solution  are  diluted  to  the  same 
volume  made  before,  and  the  titration  with  permanganate  re- 
peated, when  this  result  is  subtracted  from  that  first  obtained,  to 
obtain  the  quantity  of  permanganate  require.d  for  the  10  c.c.  of 
tannin  solution.  The  tannin,  as  well  as  gallic  acid,  if  present, 
are  mainly  oxidized  before  the  indigo,  and  therefore  oxidized 

M877:  Zeitsch.  anal.  Chem.,  16,  33;  Jour.  Chem.  Soc.,  31,  745.  KA- 
THREINER, 1879:  Dingier1  s  polyt.  Journ..  227.  481;  Zfitxch.  anal.  Chem.,  18, 
112;  a  report  fully  sustaining  this  method,  and  defending  it  against  a  criticism 
in  Mohr's  Titrirmethode.  H.  R.  PROCTER,  1877:  Chem.  News,  36,  58;  Jour. 
Chem.  Soc.,  32,  807,  "the  most  practical  method  of  tannin  analysis  yet  dis- 
covered." NEUBAUER,  Zeitsch.  anal,  Chem.,  10,  1  (1871),  after  ah  elaborate 
review  of  methods,  gives  preference  to  this.  B.  HUNT  (1885:  Jour.  Soc.  Chem. 
Ind.,  4,  263)  reports  at  length  upon  this  process,  and  advances  modifications, 
some  of  which  are  given  in  a  foot-note  further  on.  Without  these  modifica- 
tions Mr.  Hunt  finds  that  a  considerable  quantity  of  gallic  acid  may  cause  too 
high  a  result  for  tannin.  Lowenthal  made  the  first  report  of  titration  with  per- 
manganate in  presence  of  indigo  in  1860:  Jour.  /.  prakt.  Chem.,  81,  150.  The 
volumetric  use  of  permanganate  was  introduced  by  MONIER:  Compt.  rend.,  46, 


ESTIMATION  OF  TANNINS.  469 

promptly  while  the  permanganate  is  concentrated.  A  portion 
of  100  c.  c.  of  the  tannin  solution  is  now  treated  with  50  c.c.  of 
the  glue  and  common  salt  solution,  and,  after  stirring  with  100  c.c. 
of  the  acidulated  solution  of  common  salt,  again  stirred,  set  aside 
several  hours,  and  filtered.1  The  filtrate  should  be  perfectly 
clear.  Of  this  filtrate  50  c.c.  (containing  20  c.c.  of  the  tannin 
solution)  are  mixed  with  25  c.c.  of  the  indigo  solution,  and  the 
mixture  is  titrated  with  the  permanganate  solution.  Another 
25  c.c.  of  the  indigo  solution,  diluted  as  in  the  last  trial,  and 
titrated,  will  give  the  number  of  c.c.  of  permanganate  to  deduct 
for  reduction  by  indigo.  The  remainder  will  be  the  number  of 
c.c.  of  permanganate  taken  by  substances  other  than  tannin  in 
20  c.c.  of  the  tannin  solution.  Therefore  one- half  of  this  num- 
ber of  c.c.  will  be  the  number  to  deduct  for  decoloration  of  the 
permanganate  by  substances  other  than  tannin  in  10  c.c.  of  the 
original  tannin  solution.  In  the  removal  of  the  tannin,  both  the 
gelatin  solution  and  the  acid  and  salt  solution  must  be  added  in 
sufficient  quantity  to  give  a  perfectly  clear  filtrate.8  The  acid 
and  salt  solution  must  not  be  brought  in  contact  with  the  gelatin 
solution  before  the  latter  is  fully  mixed  with  the  tannin  solution. 
The  permanganate  is  to  be  added  slowly,  in  a  white  porcelain 
dish,  giving  for  reduction  as  much  as  four  minutes  with  the 
original  solution,  and  six  minutes  with  the  filtrate.  It  is  better 
to  let  the  gelatin  precipitate  stand  as  much  as  half  an  hour  be- 
fore filtering ;  if  filtered  earliei  the  filtrate  will  consume  more 
permanganate  (HEWITT).  In  preparing  the  solution  from  oak- 
bark  or  from  galls  a  few  drops  of  acetic  acid  may  be  added  for 
preservative  effect,  and  with  each  portion  of  water  the  material 
may  be  boiled  ten  or  fifteen  minutes.  It  must  not  be  forgotten 
that  tannins  are  instable.  Duplicate  titrations  should  be  made, 
and  should  agree  to  within  0.1  or  0.2  c.c.  of  permanganate. 

*B.  HUNT  (1885)  proceeds  as  follows:  100  c.c.  of  the  tannin  solution  is 
treated  (in  a  flask  taken  dry)  with  50  c.c.  of  a  solution  of  2  grams  of  gelatin 
in  100  c.c.  (freshly  filtered)*.  The  flask  is  shaken,  and  50  c.c.  of  a  saturated 
solution  of  common  salt  (containing  50  c.c.  of  undiluted  sulphuric  acid  per 
liter)  is  added,  together  with  a  little  kaolin  or  barium  sulphate.  The  solution 
filters  clear. 

2  Lflwenthal  finds  only  a  very  small  and  nearly  constant  reduction  of  per- 
manganate by  gelatin  sol'ution,  and  ascribes  this  slight  reduction  to  certain 
oxidizable  substances  with  the  gelatin.  He  infers  that  these  oxidizable  sub- 
stances are  precipitated  by  tannin  before  all  the  gelatin  is  precipitated.  By 
adding  20  c.c.  of  the  gelatin  solution  the  indigo  solution  consumed  0.4  c.c. 
more  of  permanganate  solution.  Different  kinds  of  gelatin  give  only  a  little 
difference  of  results.  Kathreiner  proposes  to  deduct  one-half  of  the  perman- 
ganate found  to  be  consumed  by  the  given  quantity  of  gelatin  solution  (Zeit. 
anal.  Chem.,  16,  33,  18,  114). 


470  TANNINS. 

The  following  schedule  of  quantities  may  be  changed  at  dis- 
cretion : 

For  10  c.c.  tannin  solution,  with  25  c.c.  indigo 

solution a  c.c. 

For  the  same  again a'  c.c. 

For  25  c.c.  indigo  solution,  diluted  as  before. .  b    c  c. 

For  oxidizable  substances  in  20  c.c.,  tannin  sol.  a  -\-  a'  —  2#— m. 

For  50  c.c.  filtrate  from  100  c.c.  tannin  sol., 
50  c.c.  glue  sol.,  and  100  c.c.  acid  and 
salt  solution c  c.c. 

For  another  50  c.c.  of  the  filtrate cf   c.c. 

For  50  c.c.  indigo  solution,  diluted  as  last 

above b'  c.c. 

For  oxidizable  substances  other  than  tannin  in 

20  c.c.  tannin  solution c-4-c'        -i, 

-^t-  -  a  =  ». 

For  tannin  in  20  c.c   original  solution.  .......         m  —  n  c.c. 

So  far  we  have  only  the  permanganate  value  of  the  original 
solution,  and,  from  this,  of  the  material  taken  to  be  estimated. 
The  permanganate  value  serves  to  compare  articles  containing 
the  same  tannin  with  each  other,  as  oak-bark  with  oak  bark,  galls 
.with  galls,  etc.  A  comparison  of  oak-bark  with  galls  must  be 
taken  with  some  reservation,  as  different  tannins  cannot  be  as- 
sumed to  act  with  the  same  equivalent.  The  permanganate  so- 
lution may  be  compared  with  a  standard  solution  of  the  purest 
gallo-tannic  acid  to  be  obtained,  or  with  any  article  of  tannin 
of  known  value.  The  conditions  of  time,  temperature,  and  dilu- 
tion must  be  kept  constant  in  all  comparisons,  both  in  extracting 
the  material  and  in  titrating  the  solutions.  According  to  the 
experiments  of  NEUBAUER,  in  1871,1  63  grams  of  crystallized 
oxalic  acid  (equivalent  to  31.4  grams  of  absolute  potassium  per- 
manganate) correspond  to  41.57  grams  purified  gallo-tanriin.* 
That  is,  10  c.c.  decinormal  oxalic  acid  solution  reduce  as  much 
permanganate  as  0.04157  grams  of  Neubauer's  purified  tannin. 
Oser  has  found  that  the  same  quantity  of  oxygen  is  required  for 
1  part  of  gallo-tannin  and  for  1.5  parts  of  oak-bark  tannin.  Then 
10  c.c.  decinormal  oxalic  acid  solution  correspond  to  0.06235 
grams  oak-bark  tannin.  These  factors  serve  provisionally,  Keu- 
bauer's  for  galls,  sumach,  and  myrabolans  ;  Oser's  for  oak- bark, 

1  Zeitsch.  anal.  Chem.,  10,  3. 

2  This  is  near  the  ratio  of  4(H2C204.2H20)  to  C14Hio09;  504  to  322;  63  to 
40.25.     The  ratio  to  Schiff's  natural  tannin  glucoside  is  that  of  8(H2C2O4 .  2H20) 
toC34Ha8022;  63  to  49.25. 


ESTIMATION  OF   TANNINS.  471 

valonia,  and  chestnut.  No  interference  in  this  estimation  (with 
the  specified  dilutions)  by  presence  of  acetic  acid,  citric  acid,  tar- 
taric  acid,  malic  acid,  cane-sugar,  dextrin,  gum,  fat,  caffeine,  or 
urea  (Cech *).  Other  agents  for  removal  of  the  tannin  in  connec- 
tion with  Lowenthal's  process  have  been  tried.  SIMANDS  (1883) 
proposes  to  use  the  gelatigenous  tissue  of  bones,  prepared  by 
digesting  bone  in  dilute  hydrochloric  acid  and  washing  away  the 
earthy  chlorides.  The  tannin  solution  is  macerated  with  the 
prepared  tissue  until  the  tannin  is  removed.  NEUBAUEK2  re- 
moves tannin  by  purified  animal  charcoal,  which  he  finds  not  to 
remove  pectous  substances.  Lowenthal  originally  used  chlori- 
nated lime  instead  of  the  permanganate. 

(2)  Method  of  GERLAND,  improved  by  RICHARDS  and  PAL- 
MER/ Volumetric  precipitation  by  potassium  antimony  tartrate 
in  presence  of  ammonium  acetate.  Either  acetate  or  chloride  of 
ammonium  causes  a  much  closer  precipitation  of  tannin,  and  pre- 
vents precipitation  of  gallic  acid.  The  standard  solution  of  Tar- 
trate of  Antimony  and  Potassium  contains  6.730  grams  of  the 
salt  dried  to  a  constant  weight  at  100°  C.  in  one  liter.  Of  this 
1  c.c.  corresponds  to  0.010  of  digallic  acid.  The  solution  of 
Ammonium  Acetate  was  prepared  by  Richards  and  Palmer  by 
saturating  glacial  acetic  acid  with  stronger  water  of  ammonia. 
The  material  for  analysis  is  dissolved  or  exhausted  so  as  to  fur- 
nish a  solution  of  150  c.c.  to  300  c.c.  in  volume  and  strong 
enough  to  contain  0.3  to  0.9  gram  of  tannin.  The  entire  solu- 
tion from  the  weighed  portion  of  material  is  now  divided  into 
three  (or  four)  aliquot  parts.  To  one  division  the  standard  solu- 
tion of  antimony  is  added  from  the  burette,  in  probable  excess, 
and  to  a  second  division  a  quantity  sure  not  to  be  an  excess  is 
added.  To  each  liquid  the  acetate  of  ammonium  solution  is 
added,  in  proportion  of  1  c.c.  (of  the  strong  solution  just  speci- 
fied) to  about  25  c.c.  of  total  liquid.  The  precipitates  are  left  to 
settle,  and  as  soon  as  clear  liquids  appear  a  drop  is  taken  from 
each  division  and  tested  on  a  hot  porcelain  plate  with  a  drop  of 

lZeitsch.  anal.  Chem.,  7.  134. 

2 1871:  Zeitsch.  anal.  Chem.,  10,  1. 

3  GERLAND,  1863:  Chem.  News,  8,  54;  Zeitsch  anal.  Chem.,  3,  419. 
GAUHE  (1863:  Zeitsch.  anal.  Chem.,  3,  131)  reports  upon  the  method,  with  ob- 
jection on  ground  of  the  difficulty  of  fixing  the  end  of  the  reaction,  and  ad- 
vises to  test  a  nitrate  of  the  titrated  liquid  for  antimony  by  zinc  and  hydro- 
chloric acid  upon  platinum  foil.  ^  RICHARDS  and  PALMER,  1878:  Sill.  Am. 
Jour.  Sci.  [3]  16,  196,  361 — modifications,  in  the  substitution  of  ammonium 
acetate  instead  of  chloride,  and  in  testing  for  excess  of  antimony.  These 
authors  report  elementary  analyses  of  the  precipitates. 


472  TANNINS. 

solution  of  sodium  thiosulphate.  If  the  antimony  have  been 
added  in  excess  the  orange  precipitate  of  antimonious  sulphide 
will  appear.  By  continued  tests  of  the  second  division  the  point 
of  least  excess  of  antimony  capable  of  recognition  is  found  ap- 
proximately. This  point  is  then  fixed  with  exactness  by  tests  of 
the  third  division  (and,  if  provided  for,  the  fourth  division). 
The  loss  by  taking  out  test-drops  is  reduced  to  a  minimum  in  the 
final  titrations.  It  is  better  to  carry  the  titrations  to  a  decided 
orange  tint  for  excess  of  antimony,  and  then  subtract  0.5  c.c. 
from  the  reading  of  the  antimony  solution  as  a  correction  for 
this  excess.  The  c.c.  X  0.01  =  the  grams  of  tannin  counted  as 
digallic  acid.  Gallic  acid  does  not  interfere  in  this  method, 
owing  to  the  ammonium  acetate.  Various  colors  occurring  in 
tanning  materials  enter  into  the  precipitates,  some  of  them 
uniting  with  the  antimony  instead  of  the  tannin,  and  therefore 
appearing  as  tannin  in  the  results.  Two  classes  of  color  sub- 
stances are  indicated  by  the  experiments  of  Kichards  and  Palmer, 
one  closely  allied  to  quercetin,  and  both  related  to  tannins  and 
tanning  agents.  With  this  method,  as  with  Lowenthal's,  true 
comparisons  between  different  tanning  agents,  as  between  oak- 
bark  and  hemlock-bark,  are  not  likely  to  be  obtained.  The  for- 
mula of  the  typical  precipitate  of  digallic  acid  is  presented  by 
the  authors  last  named  as  Sbo(C14H8O9)3.6H2O.  It  therefore 
demands  2KSbO  C^O^S  X  323  =  646)  to  3C14H10O9(3  X  322 
=  966).  The  authors'  analyses  of  precipitates  of  pure  tannins 
support  the  formula  very  well. 

^  (3)  HAGER'S  method  with  copper  oxide.1  The  addition  of 
oxide  of  copper  to  take  up  the  tannin,  which  is  estimated  from 
the  increase  in  weight  of  the  oxide,  or  (as  in  Hammer's  plan)  by 
the  decrease  in  specific  gravity  of  the  solution.  The  powdered 
material  is  extracted  first  with  water  and  then  with  alcohol, 
the  concentrated  solution  treated  with  alcohol  and  filtered,  the 
filtrate  evaporated  to  remove  all  the  alcohol,  diluted  with  water, 
filtered,  and  the  solution  made  up  to  a  determinate  volume,  of 
which  the  specific  gravity  may  be  taken.  Eecently  ignited  oxide 
of  copper,  equal  to  at  least  five  times  the  weight  of  the  tannin  to 

1  FLECK,  in  1860,  used  precipitation  with  acetate  of  copper  and  volumetric 
estimation  of  the  excess  of  copper  in  solution,  by  potassium  cyanide.  SACKUR, 
Qerberzeitigung,  31,  32,  directed  tho  ignition  of  the  copper  precipitate,  and 
WOLFF,  1862:  Zeitsch.  anal  Ohem ,  i,  103,  from  twenty-eight  analyses  gave  1 
to  1.304  as  the  ratio  between  ignited  copper  oxide  and  tannin  in  the  precipitate 
formed  by  acetate  of  copper.  To  exclude  gallic  acid  Fleck  treated  the  pre- 
cipitate with  ammonium  carbonate  solution.  Hager,  in  his  "  Untersnchun- 
gen,"  vol.  ii.  p.  115,  gives  the  method  here  presented. 


ESTIMATION  OF  TANNINS.  473 

be  found,  is  now  added,  the  mixture  warmed  for  an  hour,  and 
set  aside,  with  occasional  agitation,  for  a  day.  The  filtrate  may 
now  be  made  up  to  the  determined  volume,  the  specific  gravity 
taken,  and  the  table  consulted  for  percentage  of  tannin  corre- 
sponding to  difference  of  gravity.  The  precipitate  may  be 
washed  clean,  dried  on  the  water-bath,  and  weighed,  the  increase 
in  weight  showing  the  quantity  of  tannin.  Gallic  acid  will  be 
included.  The  method  seems  open  to  danger  of  loss  of  tannin 
by  decomposition,  especially  with  oak-bark  tannin. 

(4)  The  method  of  HAMMER  1  has  been  much  used  for  com- 
mercial analyses,  but  gives  untrustworthy  results.     The  water 
solution  of  the  material,  made  up  to  a  determinate  volume,  is 
macerated  with  dried  rasped  hide,  in  quantity  at  least  five  times- 
as  much  as  the  tannin  to  be  found,  until  the  tannin  is  wholly 
removed  from  solution.     The  filtered  liquid  is  made  up  to  the 
volume  before  noted,  and  the  specific  gravity  is  to  be  taken  both 
before  and  after  the  removal  of  the  tannin.     Difference  in  spe- 
cific gravity  -f- 1  =  specific  gravity  for  per  cent.    A  table  of  per- 
centages of  gallotannin  is  given  at  p.  477.     Pectous  substances 
are  absorbed  by  the  rasped  hide,  a  cause  of  error  unless  the  pec- 
tous  substances  are  removed  by  precipitation  with  alcohol,  which 
is  then  evaporated. 

(5)  The  method  of  WAGNER  3  gives  insufficient  results  with 
oak-bark,  but  is  serviceable  for  various  manufactured  forms  of 
tannins.     It  is  a  volumetric  precipitation  by  an  alkaloid.     4.523 
grams  of  good  sulphate  of  cinchonine,  with  0.5  gram  sulphuric 
acid  and  0.1  gram  acetate  rosaniline  or  fuchsine,  are  dissolved  in 
water  to  make  one  liter.     Each  c.c.  of  this  solution  precipitates 
0.01  gram  tannic  acid.     One  gram  of  solid  material  is  obtained 
in  clear  solution  of  about  50  c.c.  measure.     To  this  the  standard 
solution  of  cinchonine  is  added,  the  color  being  thrown  down  in 
the  precipitate.     By  a  quick  agitation  the  precipitate  soon  set- 
tles.    When  the  tannic  acid  is  all  precipitated,  the  aniline  color 
appears  in  solution.     One  gram  having  been  taken,  each  c.c.  of 
the  volumetric  solution  indicates   1  per  cent,   of  tannic  acid. 
Gallic  acid  is  not  precipitated  by  cinchonine.     CLARK  3  has  tried 
a  modification  of  this  method  for  cases  of  colored  liquids  which 

'1860:  Jour.f.praU.  Chem.,  3,  159. 

2 1866:  Zeilsch.  anal.  Chem.,  5,  9.     As  to  limits  and  deficiencies  of  this 
method  see  BRAUN,  1868:  Zeitsch.  anal.  Chem.,  7,  139. 

3  Contributions  from  Chem.    Lab.  of  Univ.  of  Mich..  1876:  Am.  Chem 
7,44.  i 


474  TANNINS. 

obscure  the  aniline  red.  It  is  the  use  of  the  standard  solution  of 
•cinchonine  in  some  excess,  filtering,  washing  sparingly,  and  ti- 
trating back  in  the  filtrate  with  Mayer's  potassium  mercuric 
iodide  solution.  This  solution  may  be  compared  with  the  cin- 
chonine  solution,  or  the  factor  of  0.0124  gram  of  cinchonine 
sulphate  for  each  c.c.  of  Mayer's  solution  may  be  used. 

Among  the  many  other  methods  for  determination  of  tannins 
are  those  with  use  of  Acetate  of  Lead  as  a  precipitant,  with  alco- 
hol ; 1  bone  gelatin  solution  with  alum ; 2  and  ferric  acetate  so- 
lution with  sodium  acetate.3  Upon  the  adaptation  of  the  several 
methods  of  estimation  to  the  several  well-known  different  tan- 
nins, see  GUNTHEK,  1870. 4 

For  estimation  of  tannin  in  leather  HAGEK'S  method  may 
be  employed.  For  the  most  part  gallic  acid  is  obtained  from 
leather  instead  of  tannic  acid.6 

Of  distinctly  known  tannins,  or  tannic  acids,  the  limits  of 
this  work  permit  only  the  following  to  be  described. 

GALLOTANNIN. — Kutgall-tannin.  Gallusgerbsaure.  Chiefly 
Digallic  acid,  or  Gallic  anhydride, 

P      TT      O C6H2(OH)2CO2H  )    ^  009 

^14^10^9  —  C6Ho(OH)3CO .      \  °  — 

(SCHIFF),  but  containing  a  portion  of  glucoside  of  digallic  acid. 
Gallotannic  Acid.  The  TANNIC  ACID  of  the  pharmacopoeias  and 
of  commerce. 

Gallotannin  is  identified  as  a  tannin  by  its  sensible  properties 
{a,  J),  its  reactions  with  gelatin,  alkaloids,  iron  salts,  and  perman- 
ganate (d)  ;  identified  as  gallotannin  by  its  fermentation  pro- 
duct (c  and  p.  467),  its  product  by  heat  (#),  its  color  with  iron 
salts,  with  molybdate,  and  the  total  bearing  of  its  qualitative 
tests  (d)  •;  estimated  by  the  method  of  Lowenthal,  Gerland,  or 
Wagner  (pp.  468-73) ;  separated  from  metallic  compounds,  iron 
inks,  and  the  fruit  acids,  by  acetic  ether  (c)  or  by  calcium  ace- 
tate (p.  21)  ;  removed,  along  with  tannins  in  general,  by  metallic 
oxides,  gelatin,  hide,  or  bone-black,  as  described  on  p.  467.  May 
be  prepared  from  galls  as  stated  on  p.  477. 

1  SCHMIDT,  1874:  Jour.  Chem.  Soc.,  28,  1183.  ALLEN,  Chem.  News,  29, 
169,  189. 

2 One  of  the  earliest  methods:  FEELING,  MULLER:  Liebig  and  Kopp's 
Jahresber.,  1853,  683;  Ding.polyt  Jour.,  151.  69;  Zeitsch.  anal  Chem.,  5,232. 

3HANDTKE,  1853:  Jour,  f.prakt.  Chem.,  58,345 

4Pharm.  Zeitsch.  f.  Russland,  1870.     Zeitsch.  anal.  Ch<m.,  10,  354. 

» As  to  the  chemical  examination  of  leather,  see  MARQUIS,  Zeitsch.  anal. 
Chem.,  5,  236  (from  Pharm.  Zeitsch.  f.  Russland)',  Hager's  "  Untersuchun- 
gen,"  ii.  116. 


GALLOTANNIN.  475 

#. — Gallotannin  is  obtained  in  light  yellowish,  lustrous  scales, 
colorless  when  purified.  Not  crystallizable,  permanent  in  the 
air  when  kept  dry,  but  turning  yellowish  in  the  light.  Obtained 
as  C14H10O9  at  140°  to  145°  C.  (LowE,  1872).  By  a  gradual  heat 
(in  a  test-tube)  it  melts,  darkens,  and  at  210°  to  215°  C.  mostly 
breaks  into  pyrogallol,  C6H6O3 ,  and  carbon  dioxide,  the  former 
subliming  in  white  crystals.  With  sudden  heat,  at  about  250° 
C.,  it  chars  with  formation  of  metagallic  acid,  C6H4O2 ,  in  the 
residue. 

b. — Tannic  acid  is  odorless  or  of  a  faint  characteristic  odor, 
and  of  a  purely  astringent  taste  and  effect.  It  does  not  appear 
to  be  absorbed  as  tannic  acid ;  at  all  events  it  is  converted  in  the 
system  into  gallic  acid,  which  is  found  as  its  product  in  the 
blood  and  urine.  It  diffuses  through  membranes  very  slowly, 
according  to  Graham  at  yf^  the  rate  of  common  salt.  It  may  be 
dialyzed  from  alcoholic  solution  (Lowe,  1872). 

c. — Dissolves  in  water  very  readily,  with  acid  reaction,  but 
decomposes  gradually  in  the  solution  with  formation  of  gallic 
acid,  turning  yellow  to  brown  in  the  light.  Freely  soluble  in 
aqueous  alcohol,  with  a  slight  formation  of  ellagic  acid  by  stand- 
ing in  the  aqueous  tincture  ;  moderately  soluble  in  aqueous  or 
water-washed  ether,  without  decomposition,  but  probably  with 
formation  of  ethyl  tannate  which  dissolves  in  the  water ;  spa- 
ringly soluble  in  absolute  alcohol;  but  slightly  soluble  in  pure 
ether,  chloroform,  benzene,  or  petroleum  benzin  ;  soluble  in  six 
parts  of  glycerin.  Acetic  ether  dissolves  tannin  freely,  and 
if  the  solvent  be  strictly  free  from  alcohol,  in  slightly  acidulous 
solution,  it  separates  the  tannin  from  aqueous  solutions  and 
from  the  fruit  acids.  If  the  tannin  be  in  metallic  combination, 
sufficient  oxalic  or  sulphuric  acid  is  iirst  added.  With  an  iron 
ink,  oxalic  acid  is  added  to  wholly  change  the  color.  The  acetic 
ether  is  shaken  in  a  tube,  and  drawn  off,  in  portions  repeated  as 
necessary,  and  the  ethereal  liquid  washed  with  water  in  the  same 
way.  Gallic  acid,  if  present,  is  obtained  with  the  tannin.  With 
the  non -alkali  metallic  bases,  and  with  the  alkaloids,  gallotannic 
acid  forms  compounds  which  are  stable  but  of  indeterminate  pro- 
portions, mostly  insoluble  in  water.  With  the  alkali  hydrates, 
in  presence  of  air,  it  begins  at  once  to  decompose,  solutions  turn- 
ing yellow  to  brown,  and  some  gallic  acid  being  formed.  Dilute 
mineral  acids  partly  precipitate  gallotannic  acid,  unchanged, 
but  on  boiling  dissociation  to  gallic  acid  occurs  (C14H10O9-f- 
II2O  =  2C7H6O5),  glucose  appearing  in  the  solution  so  far  as 
the  gallotannin  contained  glucoside  (p.  467).  The  change  to 


4;6  TANNINS. 

gallic  acid  also  takes  place  in  presence  of  the  ferment  of  nut- 
galls  and  water,  when  the  wetted  powder  is  set  aside  for  some 
weeks. 

d. — Concentrated  sulphuric  acid  sparingly  dissolves  gallo- 
tannin,  with  yellow-brown  color  turning  first  to  purple-red  and 
then  to  black  on  warming.  Nitric  acid  rapidly  oxidizes  it,  with 
formation  of  oxalic  acid  ;  chlorine,  bromine,  iodine,  and  chromic 
acid  act  violently  upon  it ;  it  promptly  reduces  permanganate,. 
reduces  silver  nitrate  on  warming,  reduces  mercuric  chloride 
and  gold  chloride,  and  reduces  alkaline  copper  solution.  It 
turns  brown  to  green  with  alkali  hydrates  and  with  atmosphe- 
ric oxidation.  It  is  very  perfectly  precipitated  by  solutions  of 
gelatin,  albumen,  and  gelatinized  starch  (distinctions  from 
gallic  acid) ;  by  cinchonine  sulphate  and  solutions  of  alkaloids 
generally  (distinction  from  gallic  acid),  some  of  the  alkaloidal 
precipitates  dissolving  easily  in  hydrochloric  acid,  and  nearly  all 
dissolving  with  acetic  acid ;  by  tartrate  of  antimony  and  potas- 
sium, this  precipitate  being  increased  by  ammonium  chloride 
solution  (in  which  that  of  gallic  acid  is  soluble)  ;  and  by  lime 
and  baryta  solutions  added  in  excess,  the  precipitates  slowly 
darkening  in  color.  Tannin  gives  no  precipitates  with  calcium 
salts  until  alkali  be  added,  the  least  excess  of  which  darkens  the 
precipitate  and  the  solution.  Ferric  chloride  and  other  ferric 
salts,  and,  still  better,  the  basic  ferroso-ferric  solutions,  give  a 
blue-black  precipitate,  dissolving  to  a  green  solution  by  excess 
of  the  iron  salt.  "With  excess  of  the  tannin  solution  the  preci- 
pitate is  permanent,  and  subsides  so  as  'to  leave  a  clear  liquid. 
The  precipitate  dissolves  readily  on  addition  of  hydrochloric 
acid,  strong  acidulation  even  destroying  the  color,  when  the  ad- 
dition of  acetate  of  sodium  will  cause  a  reproduction  of  the 
blue-black  precipitate,  which  is  not  easily  soluble  in  acetic  acid. 
The  green  solution  obtained  from  excess  of  ferric  salt  with  ace- 
tate of  sodium  does  not  give  a  precipitate,  but  shows  a  reduction 
to  ferrous  salt.  When  the  tannin  is  in  sufficient  excess,  boiling 
destroys  the  blue-black  color,  the  iron  being  reduced  to  ferrous 
salt.  Sufficient  sulphurous  or  hydrosulphuric  acid  removes  the 
color  in  the  same  way.  Ferrous  salts  (strictly  free  from  ferric) 
give  a  white  precipitate,  only  in  concentrated  solutions. — Ace- 
tate of  lead  gives  a  complete  precipitate.  Molybdate  of  am- 
monium with  tannin  presents  a  red  color  removed  by  oxalic 
acid.  Potassium  ferricyanide  in  solution  with  ammonium 
hydrate  causes  a  deep  red  color  in  solutions  of  tannin  (a  delicate 
reaction,  A.  H.  ALLEN). 


SUMACH   TANNIN. 


477 


Gallotannin,  in  solution  very  slightly  acidulated  with  acetic 
acid,  is  not  precipitated  by  adding  calcium  acetate  solution  and 
then  to  the  liquid  twice  its  volume  of  alcohol — a  separation  from 
tartaric,  citric,  malic,  and  oxalic  acids  (BARFOED  '). 

e. — Gallotannin  is  obtained  from  nutgalls  by  treating  the 
powder,  iirst  exposed  to  a  moist  atmosphere  for  twenty-four 
hours,  with  water- washed  ether  to  form  a  soft  paste,  covering 
this  for  six  hours,  and  then  expressing.  This  treatment  is  re- 
peated, and  the  expressed  liquids  spontaneously  evaporated  to  a 
syrup,  which  is  spread  on  glass  and  dried  (IT.  S.  Ph.  of  1870, 
Br.  Ph.)  Another  method  requires  maceration  of  the  powdered 
galls  in  a  mixture  of  12  parts  ether  and  3  parts  of  alcohol  of 
90$.  The  expressed  liquid  is  washed  with  a  third  of  its  volume 
of  water,  and  again  with  a  little  water,  and  the  aqueous  liquid, 
containing  the  tannin,  is  evaporated  on  the  water-bath. 

A  water  solution  of  gallotannic  acid  at  17. 5°  C.  (63.5°  F.) 
contains  as  follows  : 


Per- 
centage. 

Specific  gra- 
vity. 

Per- 
centage. 

Specific  gra- 
vity. 

Per- 
centage. 

Specific  gra<- 
vity. 

20 

1.0824 

13 

1.0530 

6 

1.0242 

19.5 

1.0803 

12.5 

1.0510 

5.5 

1.0222 

19 

1.0782 

12 

1.0489 

5 

1.0201 

18.5 

1.0761 

11.5 

1.0468 

4.5 

1.0181 

18 

1.0740 

11 

1  0447 

4 

1.0160 

17.5 

1.0719 

10.5 

1.0427 

3.5 

1.0140 

17 

1.0698 

10 

1.0406 

3 

1.0120 

16.5 

1.0677 

9.5 

1.0386 

2.5 

1.0100 

16 

1.0656 

9 

1.0365 

2 

1.0080 

15.5 

1.0635 

8.5 

1.0345 

1.5 

1.0060 

15 

1.0614 

8 

1.0324 

1 

1.0040 

14.5 

1.0593 

7.5 

1.0304 

0.5 

1.0020 

14 

1.0572 

7 

1.0283 

0 

1.0000 

13.5 

1.0551 

6.5 

1.0263 

For  Hammer's  table  of  specific  gravity  and  percentage  of 
tannin,  see  Fresenius's  "  Quantitative  Analysis." 

SUMACH  TANNIN. — From  the  fruit,  leaves,  and  branches  of 
Rhus  glabrum,  R.  coriaria,  and  other  species  of  Rhus.     STEN- 

1  "Organ,  qual.  Analyse."    Kopenhagen,  1881.     S.  58-61. 


478  TANNINS. 

HOUSE  (1861 *)  reported  it  identical  with  gallotannin.  GUNTHER 
(1871) a  found  the  tannins  of  Sumach,  Myrobalan,  and  Divi-divi 
to  be  nearly  the  same — all  agreeing  closely  with  gallotannin,  and 
not  at  all  with  oak-bark  tannin.  He  found  them  all  to  yield 
gallic  acids  by  glucosic  fermentation,  and  pyrogallols  by  subli- 
mation, and  to  react  like  gallotannin  with  salts  of  lead,  copper, 
and  iron,  with  gelatin,  antimony  tartrate,  and  permanganate. 
LOWE  (1873 3),  from  examination  of  Sicilian  sumach,  It.  coria- 
ria,  the  variety  chiefly  used  for  tanning,  declared  it  to  be  identi- 
cal with  gallotannin,  and  found  by  elementary  analysis  (as  Giin- 
ther  had  done)  numbers  nearly  those  of  digallic  acid.  Sumach 
tannin  is  a  tanning  material  much  used,  a  fact  of  interest  in 
view  of  its  agreement  with  gallotannin.  Wagner's  classification 
of  the  latter  as  a  non-tanning  agent  appears  to  be  opposed  by 
various  evidences. 

OAK-BARK  TANNIN.  Quercitannic  acid.  Quercitannin.  Ei- 
chenrindengerbsaure.  From  bark  of  various  species  of  Quer- 
cus.  Found  also  in  Black  Tea  (ROCHLEDER).  Also  the  tannin 
of  the  Elm  and  the  Willow  (JOHANSON,  Dorpat,  1875).  It  is  a 
glucoside,  with  boiling  dilute  sulphuric  acid  readily  breaking  up 
with  formation  of  oak-red,  amorphous,  and  an  uncrystallizable 
sugar,  no  gallic  acid  appearing  (GRABOWSKI,  1868);  gives  up 
water  and  forms  an  anhydride  (Em,  1884-) ;  boiling  with  caustic 
alkalies  yields  a  different  anhydride  (the  same).  The  oak-red  is 
a  phlobaphene,  found  by  itself  in  the  oak-bark.  It  does  not 
yield  pyrogallol  in  sublimation,  but  when  heated  with  potash  it 
furnishes  protocatechuic  acid  and  phloroglucin,  the  products  also 
being  obtained  from  oak  phlobaphene.  Oak-bark  tannin  is 
freely  soluble  in  water  and  in  alcohol,  in  ether  sparingly  soluble. 
It  gives  the  ink  color  with  the  basic  ferroso-ferric  solutions,  and, 
less  intensely,  with  ferric  solutions.  It  gives  precipitates  with 
acetates  of  lead,  copper,  and  iron,  and  with  gelatin  ;  is  taken 
up  by  oxides  of  lead,  copper,  and  zinc,  by  rasped  hide,  and  by 
animal  charcoal.  It  promptly  reduces  Fehling's  solution,  or  the 
permanganate,  and  chlorinated  lime  and  other  oxidizing  agents 
act  yeiy  promptly  upon  it.  This  tannin  is  the  most  important 
of  tanning  agents,  and  the  methods  of  the  estimating  tannin 
(pp.  468,  473)  have  been  mainly  framed  in  reference  to  valuation 
of  oak- bark.  At  the  same  time  it  is  one  of  the  least  stable  of 
the  tannins,  and  its  extraction  without  notable  waste  is  a  task  of 

1  Proc.  Roy.  8oc.,  u,  401. 

slnaug.  Dissertation.  Dorpat.,  Zeitsch.  anal.  Chem.,  10,  359. 

*Zeitsch.  anal.  Chem.,  12,  128;  Jour.  Chem.  Soc.,  27,  171. 


CINCHO  TA  NNIN.  479 

difficulty.  DRAGENDORFF  recommends '  to  extract  the  bark  with 
alcohol,  distil  the  spirit  in  partial  vacuum,  add  water,  filter 
quickly,  and  estimate  at  once.  Lowenthal's  method  has  the 
preference  for  this  tannin. 

CATECHUTANNIN. — From  Acacia  catechu  and  other  East  In- 
dian trees.  The  catechu,  or  cutch,  of  commerce  contains  40$  to 
55$  of  tanning  material,  and  furnishes  Catechutannic  acid  and 
Catechin.  I.  CATECHTJTANNIO  ACID  (Mimotannic  acid,  Catechin 
red)  is  obtained,  nearly  free  from  catechin,  by  treating  catechu 
with  cold  water.  It  is  precipitated  by  concentrated  sulphuric 
acid.  Boiled  with  dilute  acids  it  forms  a  dark -brown,  resinous 
body,  mimotannihydroretin  (LowE,  1869).  Gives  a  changeable 
brownish-green  color  with  ferric  salts.  Precipitates  tartrate  of 
antimony  and  potassium  (Lowe),  alkaloids,  gelatin,  and  albumen, 
and  changes  animal  membrane  to  leather.  Precipitates  lead 
acetate  (with  red  color),  dichromate  of  potassium  (brownish-red), 
and  acetate  of  copper  (with  a  leather  color).  It  reduces  silver 
nitrate  and  gold  chloride.  According  to  ETTI  (1876),  catechuic 
acid,  or,  as  he  terms  it,  catechin-red  (which  may  be  termed  a 
phlobaphene),  is  the  first  anhydride  of  catechin,  and  is  formed 
from  it  by  drying  over  sulphuric  acid,  or  by  boiling  with  sodium 
carbonate  solution.  C38II34O15  (catechutaimic  acid)  -|-  H2O  = 
2C19H18O8  (catechin).  II.  CATECHIN  (Catechuic  acid  or  Tannin- 
genie  acid).  Dissolved  from  catechin  by  boiling  water,  and  ex- 
tracted by  ether  from  dilute  alcoholic  or  concentrated  aqueous 
solutions,  crystallizing  in  needles  (ETTI,  preparation,  "  Watts's 
Dictionary,"  v-ii.  415).  It  gives  a  green  color  with  ferric  salts, 
reduces  silver  salts,  turns  purple  with  concentrated  sulphuric 
acid,  and  precipitates  albumen,  but  not  gelatin,  nor  alkaloids,  nor 
tartrate  of  antimony  and  potassium.  Fused  with  potash  it  is 
resolved  into  protocatechuic  acid  (C7H6O4)  and  phloroglucin 
(C6H603). 

MOKINTANNIN  or  mormtannic  acid.  From  Fustic,  prepared 
from  Morus  tinctoria.  Crystallizable,  with  an  intense  yellow 
color.  With  ferric  salts  it  gives  a  greenish  precipitate;  with 
lead  acetate,  a  yellow  precipitate ;  with  copper  sulphate,  a  yel- 
lowish-brown precipitate ;  with  stannous  chloride,  a  yellowish-red 
precipitate. 

CINCHOTANNIN  or  cmcliotannic  acid.  From  cinchona  barks, 
of  which  it  forms  at  the  most  3$  to  4$.  In  clear  yellow  masses, 
very  hygroscopic,  and  becoming  electric  when  rubbed,  soluble  in 

1  "Die  Analyse  von  Pflanzen,"  u.  s.  w.,  1882,  p.  167. 


480  TANNINS. 

ether,  as  well  as  in  water  and  alcohol.  It  readily  changes  to  a 
red-brown,  resinous  body,  insoluble  in  water.  By  hot  dilute 
acids  it  forms  sugar  and  cinchona-red,  the  latter  dissolving  in 
ammonia,  this  solution  being  precipitated  by  acids,  also  by 
barium  chloride  (with  a  red  color)  (REMBOLD,  1867).  With 
aqueous  alkalies,  in  exposure  to  the  air,  red  solutions  are  formed. 
Ferric  salts  form  a  green  precipitate  ;  tartrate  of  antimony  and 
potassium,  a  gray-yellow  precipitate ;  and  acetate  of  lead,  a  clear 
yellow  precipitate.  Precipitates  are  likewise  formed  with  solu- 
tions of  gelatin,  albumen,  and  starch.  Its  natural  compounds 
with  cinchona  alkaloids  are  difficultly  soluble  in  water,  but  dis- 
solve easily  in  acidulated  water.  On  fusing  w^ith  potassium 
hydrate,  protocatechuic  and  acetic  acids  are  formed. 

CAFFETANNIN  or  caffetannic  acid.  From  coffee  (Coffea  arabi- 
ca).  In  brittle  masses,  forming  a  yellow-white  powder.  But 
slightly  soluble  in  ether.  By  boiling  with  dilute  sulphuric  acid, 
or  by  digesting  with  alkali  hydrate  solutions  in  the  air,  viridic 
acid  is  formed,  with  a  blue-green  color.  Viridic  acid  is  identified 
by  giving  a  blue  precipitate  with  lead  acetate,  and  a  crimson 
color  with  concentrated  sulphuric  acid  (ROCHLEDER.  Ann.  Chem. 
Phar.,  63,  CECH,  2%/.  1868,  142).  By  long  boiling  with  potash, 
caffeic  acid  is  formed,  and  crystallizes  from  the  neutralized  solu- 
tion (RocHLEDER,  HLAsiwETz).  Ferric  chloride  gives  a  dark- 
green  color.  In  fusion  with  potassium  hydrate,  protocatechuic 
acid  and  acetic  acid  are  formed.  In  dry  distillation  pyrocatechol 
is  obtained. 

TANNIN  OF  TEA.  Dissolves  from  tea  very  sparingly  in  cold 
water,  and  but  slowly  in  boiling  water,  black 'tea  withholding  its 
tannin  from  solution  much  longer  than  green  tea.  Complete  so- 
lution requires  brisk  boiling  for  half  an  hour,  with  two  or  three 
successive  portions,  each  of  fifty  parts  of  water.1  The  average 
quantity  may  be  stated  at  11  or  12  per  cent,  of  total  tannin  in 
black  teas,  and  15  or  16  per  cent,  in  green  tea,  with  widely  sepa- 
rated extremes.2  The  character  of  tea  tannin  has  not  been  well 

1  Experiments  with  twelve  kinds  of  tea  gave  solutions  of  the  tannin,  which 
yielded,  in  tannin  percentage  of  air-dry  tea,  an  average  for  the  twelve,  as  fol- 
lows:   In  steeping  5  minutes,  0.08  per  cent.;  10  minutes,  0.55  per  cent.;  20 
minutes,  1.53  per  cent. :  30  minutes,  2.49  per  cent.,  the  digestion  being  done 
over  a  water-bath. — Report  by  the  AUTHOR,   Physician  and  Surgeon,   1880, 
p.  339. 

Fuller  determinations  are  reported  by  Mr.  GEISLER  in  Tables  III.  and  IV. 
in  the  article  "Teas  of  Commerce"  in  this  work. 

2  DRAGENDORFF  (1874)  reports  green  tea  at  12  and  black  tea  at  9.4  percent. 
A.  H.  ALLEN  (1875),  as  averages,  about  20  per  cent,  in  green  tea  (with  great 
variations),  and  10  per  cent,  in  black  tea.     EDER  (1881),  green  tea,  from  nine 


ALDER   TANNIN.  481 

established.  Stenhouse  (1861)  found  a  little  gallic  acid  in  both 
i^reen  and  black  teas,  but  no  formation  of  either  sugar  or  gallic 
acid  by  boiling  with  dilute  sulphuric  acid.  He  precipitated  the 
tannin  in  strong  decoction  by  adding  a  half-volume  of  sulphuric 
acid.  Rochleder  (1847)  found  BOHEIC  acid  (boheatannic  acid), 
giving  a  brown  color  with  ferric  salts,  along  with  iron-bluing 
tannin.  In  black  tea  he  reported  finding  quercitannic  acid.1 
The  tannin  of  black  tea  gives  a  brown  with  ferric  salts,  or  in 
alcoholic  solution  a  green  color.  Green  tea  in  infusion  gives  a 
blackish  color  with  ferric  salts,  or  blue-black  in  alcoholic  solu- 
tion. Tea  tannin  precipitates  alkaloids  generally  (cinchonine 
very  closely),  gelatin,  albumen,  and  lead  acetate. 

TANNIN  OF  HOPS.  Of  the  hop  cones,  3.67$  (BOWMAN,  1869). 
Investigated  by  ETTI  (1876,  1878)  with  results  as  follows  :  I.  HOP 
TANNIN.  Easily  soluble  in  water  and  in  dilute  alcohol,  not  in 
ether.  Acts  as  a  glucoside :  C25H24O13  (hop  tannin)  -|-  3H2O  = 
C7H6O4  (protocatechuic  acid)  +  2C6H6O3  (phloroglucin)  -\- 
C6H12O6.  Easily  dissolved  by  water  or  dilate  alcohol,  not  by 
ether.  Gives  a  dark-green  color  with  ferric  salts,  a  dirty  green 
precipitate  with  copper  sulphate,  a  yellow  precipitate  with  lead 
acetate,  a  reddish-brown  color  with  alkali  hydrates,  a  brownish- 
yellow  precipitate  with  lime  solution,  and  a  precipitate  with 
albumen,  but,  unless  previously  heated,  dry,  on  the  water  bath, 
does  not  precipitate  gelatin.  Reduces  alkaline  copper  solutions. 
By  heating  on  the  water-bath,  is  changed  to  II.  PHLOBAPHENE  OF 
HOP  [having  characteristics  of  a  tannin]  and  also  obtained  directly 
from  the  hops.  According  to  Etti,  a  glucoside  (C50H46O25),  yield- 
ing protocatechuic  acid,  phloroglucin,  and  glucose.  The  Phlo- 
baphene  dissolves  in  alcohol  and  in  alkalies,  and  is  precipitated 
from  alkaline  solutions  by  acidulation.  It  reduces  alkaline  cop- 
per solutions.  It  precipitates  gelatin  completely. 

TANNIN  OF  HEMLOCK-BARK.  Abies  Canadensis.  Extensively 
used  as  an  American  tanning  material.  The  bark  sometimes 
yields  13-14$  tannin. 

ALDER  TANNIN.     From  Alnus  glutinosa.     With  acids  does 

samples,  12.4  percent. ;  black  tea,  from  twenty-five  samples,  10.1  per  cent.  A 
report  by  the  Author,  in  1876.  gave  12  per  cent,  as  the  average  of  twenty  kinds 
of  green  and  black  tea.  Much  higher  figures  have  been  given :  WIGNER,  1875, 
33  per  cent,  to  45  per  cent.  But  the  best  present  data  are  those  given  by  Mr. 
GEISLER  in  the  article  on  "  Teas  of  Commerce"  in  this  work. 

'•  The  results  certainly  indicate  that  the  sweating  operations  in  manufacture 
of  black  tea  so  act  upon  the  tannin  as  to  convert  a  smaller  part  into  other  sub- 
stances and  modify  the  remainder. 


482  TANNINS. 

not  yield  sugar  (STENHOUSE).     From  the  wood,  an  iron-greening; 
from  the  bark,  an  iron-bluing  tannin.     Used  for  tanning. 

CHESTNUT  TANNIN.  From  species  of  Castanea.  Boiled  with 
dilute  sulphuric  acid,  yields  chestnut-red,  a  phlobaphene  or  resin- 
like  precipitate  of  cherry-red  color.  With*  ferric  chloride  gives 
a  deep  green  color.  Does  not  precipitate  tartrate  of  antimony 
and  potassium.  Fused  with  potash,  forms  protocatechuic  acid, 
C6IL(OH)2CO2H,  and  phloroglucin,  C6H3(OH)3. 

For  other  tannins  see  Dragendorffs  u  Die  Analyse  von 
Pflanzen,"  article  165,  pp.  162-168  ;  Husemann's  "  Die  Pflan- 
zenstoffe,"  by  general  index  ;  Jour.  Chem.  /&><?.,  Abstracts,  etc. 

INKS. — The  black  inks  and  writing  fluids  in  most  general  use 
have  gallotannin,  taken  as  nutgalls,  and  iron  as  oxidized  in  the 
air  from  ferrous  sulphate,  as  their  essential  basis.  The  gallic 
acid  of  the  galls  is  quite  as  serviceable  as  the  tannic  acid,  in  fact 
both  are  required,  and  inks  are  made  with  use  of  tannic  and  gal- 
lic acids  and  iron.  The  color  compound  of  iron  with  gallic  acid 
and  gallotannin  in  inks  is  mostly  not  in  solution,  but  is  in  very 
fine  suspension,  usually  with  help  of  a  slightly  viscid  menstruum, 
by  use  of  a  gurn.  Besides  galls  and  their  products,  logwood  is 
next  most  used  in  inks,  both  with  galls  and  without.  It  con- 
tains a  tannin,  as  well  as  the  color  substance  hsematoxylin. 
Logwood  and  alum  or  other  salt  form  the  basis  of  purplish  inks. 
Logwood  and  chromate  of  potassium  make  a  clear  liquid  ink  that 
has  been  much  esteemed.  Chrome  alum  has  also  been  used  with 
logwood.  Sumach  has  been  used  instead  of  galls.  Some  of  the 
mitgall  inks  contain  a  little  acetic  acid,  added  as  vinegar.  Some 
of  the  gallic  inks  have  the  addition  of  sulphindigotic  acid  or  of 
sodium  sulphindigotate  (indigo-carmine).  Aniline  dyes  of  va- 
rious colors  are  used  as  a  part  or  the  whole  of  the  color  of  black 
and  colored  inks.1 — Blue  inks  are  made  of  prussian  blue  and 
oxalic  acid,  or  "  soluble  prussian  blue "  and  a  little  oxalic  acid, 
also  of  anilines.  Red  inks  are  made  of  cochineal,  or  its  product, 
carmine,  with  ammonia  or  carbonate  of  ammonia.  Cream  of 
tartar  and  sodium  carbonate  are  also  used  as  solvents  of  carmine. 
Brazil- wood  is  employed  for  another  class  of  red  inks,  and  red  to 
violet  inks  made  from  aniline  dyes  have  been  common. — -India 
ink  and  China  ink  consist  of  finely  divided  carbon,  and  are 
wholly  insoluble,  but  very  durable  inks  of  good  service  for  the 
pen  have  been  made  by  a  suspension  of  india  ink  in  dilute  hy- 

1  A  black  ink  very  highly  recommended  is  made  of  pigrosine  (an  aniline 
black),  potassium  dichromate,  and  gelatin.  Directions  in  New  Rem.,  1883, 
12,  27.  Modified  for  copying  ink,  ibid.,  1883,  12,  250  (Aug.) 


CHEMICAL  EXAMINA  TION  OF  WRITINGS.     483 

drochloric  acid  or  in  potassium  hydrate  solution. —  Copying  inks 
are  made  by  addition  of  glycerin  to  any  ink,  the  glycerin  tak- 
ing the  place  of  an  equal  volume  of  water. — All  inks  containing 
tannin,  logwood,  etc.,  are  liable  to  mould,  and  essential  oils  are 
often  added  as  preservatives.  Salicylic  acid  is  a  good  preser- 
vative, and  carbolic  acid  usually  prevents  decomposition. — For 
indelible  inks  for  marking  linen,  solution  of  silver  nitrate,  with  a 
little  india  ink,  has  been  used.  Gold  and  platinum  have  been 
used  in  the  same  way,  staining  by  reduction.  Aniline  marking 
inks  are  in  use.  Molybdenum  chloride  is  also  taken  as  the  color- 
ing agent  of  a  marking  ink. — Printer's  ink  is  finely  divided 
carbon  in  mixture  with  linseed  oil,  with  lesser  additions  of  tur- 
pentine, resins,  etc. — Hectographic  ink  is  of  aniline  color 
(methyl- violet  1,  water  7,  glycerin  2). — As  to  the  composition 
of  inks,  see  the  article  by  Prof.  Silliman  in  "Johnson's  Cyclo- 
paedia1' ;  also  "  Watts's  Dictionary,"  iii.  272,  viii.  1090;  and  an 
Inaugural  Dissertation  of  O.  L.  Wilson,  Univ.  Mich.,  1881. 

CHEMICAL  EXAMINATION  OF  WRITINGS,  and  the  discharge  of 
Ink-Stains. — Such  examination  may  give  some  indication  of  the 
nature  of  the  ink  used,  and  may  serve  to  show  whether  two  por 
tioris  of  writing  were  written  by  the  same  ink  or  not,  and  at  the 
same  period  of  time  or  not,  also  whether  ink-marks  have  been 
discharged  by  chemical  agents.  A  minute  inspection  is  iirst 
made  under  a  magnifying-glass,  or  a  microscope  of  a  power  of 
not  more  than  ten  diameters.  Differences  of  lustre,  color,  shade, 
and  absorption  into  the  paper  are  to  be  noted,  and,  when  lines 
cross  each  other,  which  lies  uppermost.  In  the  chemical  treat- 
ment  the  reagents  most  used  are,^/',^,  a  solution  of  oxalic  acid, 
one  part  in  fifteen  parts  of  water,  and,  second,  hydrochloric  acid  of 
12.5$.  These  may  be  applied  by  a  quill  pen  through  the  writ- 
ing, and  the  result  noted  as  the  reagent  dries.  Writing  with 
gallic  inks,  of  not  over  two  days'  standing,  is  discharged  l3y  the 
oxalic  acid  in  one  application  to  a  light  gray ;  when  older  the  ink 
color  resists  longer  and  a  deeper  gray  remains.  Logwood  ink 
writings,  under  oxalic  acid,  mostly  turn  to  reddish  tints.  Aniline 
ink-marks  are  not  altered  by  oxalic  acid.  Alizarin  ink-marks 
turn  bluish.  By  treatment  with  the  hydrochloric  acid  (not 
warmed),  fresh  gallic  ink- marks,  not  over  one  day  old,  turn  yel- 
low ;  older  marks,  yellow-gray.  Logwood  ink- writings  turn 
reddish  or  reddish-gray ;  those  of  alizarin  ink  turn  greenish  ;  and 
those  of  aniline  inks,  reddish  to  brownish-gray.  Following 
treatment  with  acids  and  drying,  moist  vapor  of  ammonia,  or 
blotting-paper  wet  with  solution  of  ammonia,  may  be  applied. 


484  TANNINS. 

Under  this  alkali  the  marks  darken  again  in  different  degrees 
and  colors,  those  of  logwood  inks  turning  of  a  dark  violet  to 
violet-black.  In  distinguishing  between  ink-marks  as  to  their 
age,  treatment  with  ammonia  solution  of  ten  per  cent,  is  often 
quite  decisive,  old  ink-marks  dissolving  away  with  more  diffi- 
culty. 

Other  reagents  employed  are  dilute  sulphuric  acid,  dilute 
nitric  acid,  sulphurous  acid  solution,  sodium  hydrate  solution, 
chlorinated  lime  solution,  stannous  chloride  solution,  and  stannic 
chloride  solution.  The  reagent  may  be  absorbed  by  blotting- 
paper  a  few  seconds  after  its  application,  or  allowed  to  dry. 
After  treatment  with  ammonia,  solution  of  gallic  acid  or  solution 
of  cupric  chloride  may  be  employed.  Control-tests,  with  writ- 
ings of  known  inks  and  ages,  should  not  be  neglected.  Obviously 
it  may  be  possible  to  show  that  given  marks  were  or  were  not 
made  with  the  same  inks,  when  not  possible  to  identify  the  con- 
stituents of  the  inks. 

The  falsification  or  alteration  of  writings  is  undertaken  by 
erasing  or  by  application  of  bleaching  agents.  After  erasing 
the  spot  is  often  rubbed  over  with  powder  of  alum  or  of  sanda- 
rac,  or  is  coated  with  a  little  gelatinous  sizing.  The  bleaching 
agents  used  are  commonly  oxalic  acid,  citric  acid,  hydrochloric 
acid,  chlorine-water  or  chlorinated  lime  solution,  and  bisulphite 
of  sodium.  In  the  investigation  the  sizing  material  of  the  paper 
must  be  considered,  as  well  as  any  coloring  agents  used  in  its 
manufacture.  Moistened  litmus-paper,  or  other  indicator,  may 
be  applied  to  indicate  the  presence  of  fixed  acids.  Application 
of  ammonia  vapor  or  alcoholic  solution  of  ammonia  may  restore 
colors  discharged  by  acids.  Tests  for  iron  salts  left  after  dis- 
charge of  iron  ink-marks  may  be  made  by  alcoholic  solution  of 
gallic  and  tannic  acids,  or  by  water  solution  of  one  of  the 
cyanogen  reagents.  Copper  salts  may  also  be  tested  for.  Among 
other  experiments,  the  application  of  iodine  vapor,  over  a  beaker, 
has  been  resorted  to.  To  reveal  faded  marks  of  iron  ink  the 
paper  may  be  moistened  with  solution  of  potassium  sulphocya- 
nide,  and  exposed  to  vapor  of  hydrochloric  acid.1 

To  remove  ink-stains  from  white  cotton  or  linen  fabrics, 
solution  of  oxalic  acid  or  dilute  hydrochloric  is  most  used,  and 
does  well  with  stains  of  nutgall  ink.  After  hydrochloric  acid, 
granulated  tin  or  zinc  may  be  applied  to  favor  reduction  and  re- 
moval of  iron.  For  colored  cloths  of  cellulose  fibre,  and  for 

i  Further  upon  the  chemical  examination  of  ink  writings  see  Hager's  "  Un- 
tersuchungen,"  ii.  599;  and  W.  THOMPSON,  1880:  Chem.  News,  42,  32.  Also 
"  Rogers  on  Expert  Testimony,"  1883,  p.  182. 


TARTARIC  A  CID.  485 

woollens,  repeated  washings  with  citric  acid  may  be  tried,  but 
some  colors  will  be  changed  by  it.  Strong  solution  of  pyro- 
phosphate  of  sodium  has  been  employed,  and  may  be  used  after 
treatment  with  tallow.  Aniline  ink-stains  are  in  some  cases 
removed  by  strong  alcohol  acidulated  with  acetic  acid.1 

TARTARIC  ACID. 


H2C4H4O6  ==  C2H2  j  $**  )a     = 


Ordinary  Tartaric  or  Dextrotartaric  Acid.  Weinsdure.  —  Yery 
widely  distributed  in  fruits  and  other  parts  of  plants,  chiefly  as 
potassium  acid  tartrate,  calcium  normal  tartrate,  and  free  acid. 
Manufactured  from  the  grape-wine  deposits  of  acid  tartrate  by 
forming  calcium  tartrate,  and  transposing  this  with  dilute  sul 
phuric  acid.  Largely  used,  as  free  acid  and  as  acid  tartrate  of 
potassium  (cream  of  tartar),  in  calico  printing,  and  in  baking 
powders,  effervescent  carbonates,  medicinal  preparations,  etc. 
The  normal  tartrate  of  potassium  and  sodium,  the  normal  tartrate 
of  potassium,  and  the  basic  tartrate  of  antimony  and  potassium 
are  in  common  use. 

Tartaric  acid  is  distinguished  by  the  form  of  its  crystals,  its 
odor  when  heated,  and  its  blackening  by  sulphuric  acid  (a)  ;  by 
its  precipitations  as  potassium  acid  salt,  calcium  salt,  and  lead 
salt,  by  Fenton's  color  test,  and  by  its  extent  of  reducing  power 
(d).  Methods  of  separation,  as  a  free  acid,  and  from  its  salts,  by 
solvents  and  precipitants,  are  noted  in  e.  It  is  estimated,  as  free 
acid  or  acid  tartrate,  volumetrically  and  gravimetrically  (f  )  ;  in 
Liquors  of  Citric  and  Tartaric  Acids,  by  precipitation  and  titra- 
tion  ;  in  Tartars,  Argols,  and  Lees,  by  various  methods  ;  in  Fruit 
Juices,  from  a  lead  precipitate  (p.  488)  ;  in  pure  watery  solutions, 
by  specific  gravity.  Impurities,  g.  Cream  of  Tartar  and  cal- 
cium tartrate,  p.  496.  Examination  of  Cream  of  Tartar,  p.  498. 
Baking  Powders,  constituents,  p.  500  ;  valuation,  pp.  501-504. 

a,  b.  —  Dextrotartaric  acid  is  found  in  commerce  in  large, 
hard,  fragmentary,  permanent,  water-white  crystals,  or  in  an 
opaque-  white,  fine  powder.  The  crystals,  H2C4H4O6,  are  mo- 
noclinic,  oblique  rhombic  prisms,  hemihedral,  the  most  perfect 
ones  showing  two  corners  truncated  on  the  same  side  while  the 
two  opposite  corners  are  not  cut  off  They  are  pyro-electric, 
shining  in  the  dark,  after  friction.  The  specific  gravity  is  1.764. 
The  dry  acid  melts  at  135°  C.,  forming  a  clear  liquid,  which  at 
170°  C.  is  converted  into  metatartaric  acid,  deliquescent  and  un- 

1  For  directions  for  removal  of  stains  and  spots  of  many  kinds  see  New 
Remedies,  March,  1882,  n,  74;  Am.  Jour.  Phar.,  Dec.,  1880,  52,  632;  New 
Remedies,  Jan.,  1883,  12,  24. 


486  TARTARIC  ACID. 

crystallizable,  and  at  about  200°  0.  forms  anhydrides,  some  of 
which  do  not  dissolve  readily  in  water.  At  a  higher  tempera- 
ture the  mass  blackens  and  evolves  vapors  with  a  strong  odor  of 
burnt  sugar  or  caramel.  Concentrated  sulphuric  acid  dissolves 
dry  tartaric  acid  in  the  cold  without  color,  the  mixture  charring 
when  warmed. 

c. — Tartaric  acid  is  soluble  in  less  than  its  weight  of  cold 
water,  in  about  three  parts  of  alcohol  (of  absolute  alcohol,  four 
parts — BOUKGOIN,  1878),  in  250  parts  of  absolute  ether,1  soluble 
in  methyl  alcohol  and  in  amyl  alcohol,  insoluble  in  chloroform 
and  in  benzene.  The  water  solution  rotates  the  plane  of  polar- 
ized light  to  the  right.  Decomposition  soon  occurs  in  water 
solution,  with  a  fungoid  growth  containing  nitrogen. 

The  normal  tartrates  of  potassium,  sodium,  and  ammonium, 
and  the  acid  tartrate  of  sodium,  are  freely  soluble  in  water;  the 
acid  tartrates  of  potassium  and  ammonium  are  sparingly  soluble 
in  water;  the  normal  tartrates  of  non-alkali  metals  are  insolulle 
or  only  slightly  soluble  in  water,  but  mostly  dissolve  in  solution 
of  tartaric  acid.  Tartrates  are  insoluble  in  absolute  alcohol. 
Aqueous  alkalies  dissolve  most  of  the  tartrates  (those  of  mercury, 
silver,  and  bismuth  being  excepted),  generally  by  formation  of 
soluble  double  tartrates,  such  as  K6Fe2(C4H4O6)6,  a  scale  prepa- 
ration of  the  pharmacopoeia,  For  this  reason  tartaric  acid  pre- 
vents the  precipitation  of  salts  of  iron  and  many  other  heavy 
metals  by  alkalies.  Alkali  normal  tartrates  also  hinder  the  pre- 
cipitation of  lead  and  barium  sulphates,  manganese  sulphide,  and 
ferrous  ferricyanide.2  Hydrochloric,  nitric,  and  sulphuric  acids 
transpose  tartrates. 

d. — Lime  solution,  added  to  free  tartaric  acid  solution  until 
the  reaction  is  alkaline,  ffives  a  precipitate  without  warming 
(distinction  from  citric  acid,  which  precipitates  only  when  heat- 
ed). With  a  neutral  tartrate  the  precipitation ^  is  obtained  by 
adding  much  of  the  lime  solution  or  by  boiling.  Calcium 
chloride  solution  is  precipitated,  not  by  free  tartaric  acid,  but 
by  neutral  tartrates,  in  solutions  not  very  dilute,  and  when 
neither  the  tartrate  nor  the  lime  salt  is  in  large  excess.  The 
precipitate,  calcium  tartrate  (see  p.  498),  when  freely  formed  is 
voluminous  and  amorphous,  and  dissolves  in  about  1000  parts  of 
cold  water,  in  an  excess  either  of  the  tartrate  or  the  calcium 
salt,  in  acetic  acid  (distinction  from  oxalafce),  and  in  ammonium 

1 J.  NESSLER.  1879:  Zritsch.  anal.  Chemie,  18,  230. 
9SpiLLEB,  1858:  Jour.  Chem.  Soc.,  10,  110. 


TARTARIC  ACID.  487 

chloride.  On  standing,  or  in  dilute  solutions  at  its  first  forma- 
tion as  a  delayed  precipitate,  it  assumes  a  crystalline  form,  much 
less  easily  seen  than  the  amorphous  form,  and  less  easily  dis- 
solved by  any  of  the  solvents  above  named,  hardly  soluble  by 
acetic  acid.  The  calcium  tartrate  precipitate  is  soluble  in  cold 
strong  potassa  solution  (distinction  and  partial  separation  from 
citrate  or  oxalate) ;  the  precipitate  reappearing  when  the  liquid 
is  heated,  and  again  dissolving  as  it  cools.  This  reaction  is  best 
obtained  with  the  washed  calcium  tartrate  precipitate  ;  an  ex- 
cess of  calcium  chloride  in  the  mixture  interferes. — Calcium 
sulphate  solution  is  not  precipitated  by  free  tartaric  acid  (diffe- 
rence from  oxalic  acid),  but  gradually  gives  a  slight  precipitate 
with  tartrates  (difference  from  citrates). 

Solution  of  potassium  acetate,  or  citrate,  precipitates  free 
tartaric  acid,  as  potassium  hydrogen  tartrate,  KHC4H4O6.  The 
precipitate  forms  slowly,  in  trirnetric  crystals,  which  subside, 
the  formation  being  favored  by  stirring  with  a  glass  rod.  The 
precipitate  dissolves  in  alkalies  by  formation  of  normal  tartrates. 
In  this  test  a  neutral  or  alkaline  liquid  is  to  be  strongly  acidu- 
lated with  acetic  acid,  which  does  not  at  all  dissolve  the  precipi- 
tate. If  a  free  mineral  acid  be  present,  only  so  much  the  more 
reagent  potassium  acetate  is  to  be  added.  The  precipitate  is 
soluble  in  about  180  parts  water  at  common  temperatures  and 
in  15  parts  boiling  water,  insoluble  in  alcohol,  and  not  apprecia- 
bly soluble  in  fifty  per  cent,  alcohol.  Two  volumes  of  ordinary 
alcohol  may  be  added  to  one  volume  of  the  aqueous  solution, 
with  strong  acetic  acidulation,  to  hold  other  salts  in  solution. 
This  precipitate  is  a  separation  from  citric,  malic,  and  oxalic 
acids,  and  from  salts  of  many  inorganic  acids  as  well.  In  the 
latter  case  care  must  be  taken  that  the  alcohol  does  not  throw 
down  inorganic  salts  of  potassium.  Further,  see  p.  490. 

Tartaric  acid  is  distinguished  from  citric  acid,  in  crystal,  and 
the  former  is  detected  in  a  crystalline  mixture  of  the  two  acids, 
as  follows : l 

A  solution  of  4  grams  of  dried  potassium  hydrate  in  60 
cubic  centimeters  of  water  and  30  cubic  centimeters  of  90  per 
cent,  alcohol  is  poured  upon  a  glass  plate  or  beaker-bottom  to 
the  depth  of  about  0.6  centimeter  (one-fourth  inch).  Crystals 
of  the  acid  under  examination  are  placed,  in  regular  order,  three 
to  five  centimeters  (one  to  two  inches)  apart,  in  this  liquid,  and 
left  without  agitation  for  two  or  three  hours.  The  citric  acid 
crystal  dissolves  slowly  but  completely  and  without  losing  its 

1  Hager's  "  Untersuchungen,"  ii.  103. 


488  TARTARIC  ACID. 

transparency.  The  tartaric  acid  crystal  (or  the  crystal  contain- 
ing tartaric  acid)  becomes,  in  a  few  minutes,  opaque  white  (in  a 
greater  or  less  degree),  and  continues  for  hours  and  days  slowly 
to  disintegrate  without  dissolving  and  with  gradual  projection 
of  spicate  crystals,  fibrous  and  opaque. 

Solution  of  lead  acetate  precipitates  free  tartaric  acid  or 
tartrates,  as  white  normal  tartrate  of  lead,  very  slightly  soluble 
in  water,  insoluble  in  alcohol,  but  slightly  soluble  in  acetic  acid, 
readily  soluble  in  tartaric  acid,  in  ammonia,  and  in  tartrate  of 
ammonium  solution,  and  freely  soluble  in  ammoniacal  solution 
of  tartrate  of  ammonium  (distinction  from  Malate),  somewhat 
soluble  in  chloride  of  ammonium. 

A  color  test  is  made,  after  removal  of  heavy  metals  or  oxid- 
izing agents,  by  adding,  to  the  acid  or  its  alkali  salt,  a  little  fer- 
rous sulphate  solution,  then  a  little  hydrogen  peroxide,  or  chlo 
rinated  soda  solution,  or  acidulated  permanganate  solution  (the 
first  of  these  three  being  the  best) — avoiding  an  excess  of  the 
oxidizing  agent — lastly  an  excess  of  potassium  or  sodium  hydrate 
solution,  when  a  tine  violet  color  gives  evidence  of  the  presence 
of  tartaric  acid.1 

Solution  of  silver  nitrate  precipitates  solutions  of  normal 
tartrates  (not  free  tartaric  acid)  as  white  argentic  tartrate,  soluble 
in  ammonia  and  in  nitric  acid.  On  boiling  the  precipitate  turns 
black,  by  reduction  of  silver,  some  portion  of  which  usually 
deposits  as  a  mirror-coating  on  the  glass.  The  reduction  to  the 
specular  metallic  form  may  be  obtained,  from  even  slight  quan- 
tities of  tartaric  acid,  as  follows  :  Acidulate  the  solution  with 
nitric  acid,  add  some  excess  of  silver  nitrate  solution,  filter  out 
any  precipitate  (not  tartrate),  and  add  very  dilute  ammonia-water 
to  slight  alkaline  reaction.  If  a  precipitate  of  silver  tartrate 
appears,  add  the  ammonia  till  it  is  nearly  all  redissolved,  filter, 
heat  to  near  the  boiling  point  for  a  minute,  and  set  aside  in  a 
warm  place.  (Citric  acid  does  not  effect  this  reduction,  or  only 
on  long  boiling.)  Free  tartaric  acid  does  not  reduce  silver  from 
the  nitrate. 

Permanganate  of  potassium  solution  is  reduced  very  slowly 
by  free  tartaric  acid,  but  quickly  by  alkaline  solution  of  tar- 
trates, with  precipitation  of  manganese  dioxide,  brown  (a  dis- 
tinction from  Citrates,  which  reduce  permanganate  but  very 
slowly,  and  then  form  green  solution  of  manganate,  more  than 
precipitate  of  dioxide). — Dichromate  of  potassium  solution  is 

1  FENTON,  1881:  Chem.  News,  43,  110;  Jour.  Chem.  Soc.,  40,  655;  New 
Remedies,  10,  147. 


TARTARIC  ACID.  489 

readily  reduced  by  tartaric  acid,  with  appearance  of  a  green 
color  and  slight  effervescence.  For  use  of  this  test  in  distinction 
from  malic,  citric,  and  succinic  acids,  see  under  Malic  acid,  at  c. 
In  the  detection  of  tartaric  acid  in  Citric  acid  of  commerce,, 
CAILLETETI  directs  to  take  10  c.c.  of  saturated  dichromate  solu- 
tion, add  1  gram  of  the  acid  to  be  tested,  and  stir,  not  warming. 
After  ten  minutes'  standing  he  found  pure  citric  acid  to  remain 
orange -colored ;  that  with  1  per  cent,  tartaric  acid,  coffee-col- 
ored ;  with  5  per  cent,  tartaric  acid,  black-brown.  Among 
the  products  of  the  oxidation  of  tartaric  acid  by  permanganate 
and  chromate  are  formic  acid,  carbon  dioxide,  and  water. — Cop- 
per sulphate  with  potassium  hydrate  is  not  reduced  by  tartaric 
acid. — Gold  chloride  solution  is  reduced  only  in  solution  made 
alkaline  with  potassium  hydrate,  when  a  black  precipitate  of 
aurous  chloride  is  formed. 

e. — Tartaric  acid  may  be  separated  from  tartrates  by  adding 
its  equivalent  quantity  of  sulphuric  acid  and  extracting  with 
alcohol  (in  which  most  sulphates  are  insoluble).  Free  tartaric 
acid  may  be  taken  out  of  water  solutions  by  agitation  with  amyl 
alcohol,  which,  after  standing,  is  decanted.  From  the  other 
fruit  acids  (citric,  malic,  oxalic),  and  most  inorganic  acids,  it  is 
best  separated  by  its  precipitation  as  bitartrate  (j),  also  approxi- 
mately separated  by  its  calcium  reactions  (£,  and  in  detailed 
scheme  under  Malic  acid,  d).  From  tannin  and  gallic  acid  as 
noted  under  Gallotaimin,  p.  477.  From  acids  whose  lead  salts  are 
soluble  in  water,  by  treatment  with  lead  acetate,  followed  by 
hydrogen  sulphide,  etc. 

f. — Quantitative. — Free  tartaric  acid,  if  unmixed  with  other 
acids  or  salts  which  neutralize  alkalies,  may  be  estimated  volume- 
trically  by  standard  alkali  solutions,  the  point  of  saturation  in 
normal  tartrate  being  sharply  defined  by  the  tint  of  litmus  or 
by  phenol-phthalein.  Weighing  0.750  gram,  the  number  of  c.c. 
of  decinormal  alkali  solution  required  equals  the  number  per  cent, 
of  the  acid.  Each  c.c.  of  normal  alkali  neutralizes  0.075  gram  of 
acid. — The  acid  tartrate  of  potassium,  obtained  by  precipitation, 
as  directed  below,  may  also  be  exactly  estimated  by  acidimetry,. 
when  each  c.c.  of  normal  alkali  solution  required  indicates  0.150 
gram  of  tartaric  acid.  Another  way,  properly  used  in  some  cases 
but  having  no  advantage  if  the  acid  tartrate  be  pure,  is  to  gradu- 
ally ignite  the  dried  precipitate  of  acid  tartrate,  at  a  low  red  heatr 

1  Jahresb.  d.  Phar.,  1877,  316;  from  Jour,  de  Phar.  et  de  Chim.  [4]  25, 
573;  Zeitsch.  anal.  Chem.,  17,  499. 


490  TARTARIC  ACID. 

till  vapors  no  longer  rise,  cool  and  treat  the  charred  mass  (con- 
taining all  the  potassium  as  carbonate)  thoroughly  with  water 
and  a  slight  excess  of  volumetric  acid  from  the  burette,  boil,  and 
filter,  and  wash  well,  and  titrate  back  with  volumetric  alkali. 
Each  c.c.  of  normal  acid,  after  deduction  of  the  number  of  c.c. 
of  corresponding  alkali  solution  used,  indicates  (the  same  as 
when  measuring  the  acid  precipitate  with  alkali)  0.150  gram  of 
tartaric  acid  in  the  bitartrate.  Much  care  is  needed  to  avoid  loss 
during  ignition. 

Tartaric  acid  is  capable  of  estimation  volumetrically  by  oxidiz- 
ing agents.  A  method  with  use  of  dichromate  for  this  purpose 
has  been  proposed  (compare  Citric  Acid,  c) .  The  use  of  permanga- 
nate for  titration  of  tartaric  acid  in  metallic  salts  has  been  "re- 
ported by  F.  W.  CLARKE,  1881.1 

The  gravimetric  determination  most  generally  applicable  is 
that  by  precipitation  as  potassium  hydrogen  tartrate,  though 
this  precipitate  is  more  easily  and  surely  treated  volumetrically. 
The  reagent  is  the  acetate  of  potassium,  or,  if  iron  or  alumi- 
num be  present,  citrate  of  potassium  (WARINGTON);  and  if  the 
tartaric  acid  is  in  neutral  salts,  acetic  acid  should  be  added 
with  the  acetate  (or  citric  acid  with  the  citrate)  to  a  decided  acid 
reaction,  and  enough  to  fully  prevent  the  formation  of  the  freely 
soluble  normal  tartrate.  In  simple  mixtures  the  acetate  is  better 
than  the  citrate,  arid  excess  of  either  is  to  be  avoided.  By  use 
of  alcohol  the  precipitate  may  be  made  complete,  and  may  be 
washed  without  loss.  The  moist  precipitate,  just  washed  volume- 
trically clean,  may  be  titrated  (either  with  the  filter  or  transfer- 
red) with  standard  alkali,  as  directed  above,  or,  after  washing 
gravimetrically  clean  and  drying  at  100°  C.,  the  precipitate  may 
be  weighed.  KHC4H4O6  :  H2C4H4O6 : :  1  :  0.797.  The  strength 
of  alcohol,  in  the  precipitation  and  in  the  washing,  should  be  at 
least  50$  by  weight,  unless  some  other  agent  is  depended  upon 
to  diminish  the  solubility  of  the  precipitate.  If  no  interference 
is  apprehended  the  strength  may  be  60  to  65$. a  If  sulphates 

1  Am.  Ghem.  Jour.,  3,  201. 

2  The  author  has  found  the  precipitate  to  be  washed  continuously  with  50 
per  cent,  alcohol  without  weighable  loss       FLEISCHER,  1870:    Zeitsch.  anal. 
Chem.,  9,  331;  Am.  Ghem.,  i,  352.  using  the  precipitate  for  the  determination 
of  potassium,  finds  it  insoluble  in  50  per  cent,  alcohol.     (If  sodium  be  present, 
to  avoid  its  precipitation  he  directs  to  add  ammonium  chloride.)     CASSAMAJOR, 
1876:  Am.  Chem.,  7,  84,  finds  that  alcohol  of  about  60  percent,  is  needed  to 
preserve  the  precipitate  from  waste.     Strong  acidulation  with  acetic  acid  has 
no  solvent  effect  on  the  precipitate.     WARINGTON  found  tartaric  acid  to  have 
no  solvent  power,  citric  acid  a  slight  solvent  power,  and   hydrochloric  acid 
much  solvent  power,  when  applied,  in  water,  to  the  precipitate. 


TARTARIC  ACID.  491 

are  present  they  are  liable  to  be  precipitated  by  the  alcohol,  and 
will  interfere  with  the  gravimetric  treatment  of  the  precipitate. 
A  sulphate  of  aluminium,  or  iron,  or  any  other  salt  that  will 
neutralize  an  alkali,  will  interfere  likewise  with  the  volumetric 
treatment ;  but  a  sulphate  of  calcium,  or  any  salt  that  does  not 
neutralize  an  alkali,  may  be  permitted  to  go  into  the  precipitate 
if  this  is  to  be  volumetrically  determined.  Further,  as  ascertained 
by  WARINGTON  and  applied  in  his  methods,  given  below,  the 
precipitate  is  but  little  soluble  in  chloride  of  potassium  solu- 
tion. 

For  determination  of  tartaric  acid  in  complex  Liquors  of 
Citric  and  Tartaric  Acids,  occurring  in  the  manufacture  of 
these  acids,  WARINGTON  1  directs  as  follows  :  A  quantity  of  the 
liquor  containing  from  2  to  4  grams  of  tartaric  acid,  and  of  30 
to  40  c.c.  in  volume,  is  treated  with  citric  acid  unless  free  sul- 
phuric acid  is  present,  then  treated  with  a  saturated  solution  of 
normal  potassium  citrate,  added  in  measured  quantity  drop  by 
drop  with  constant  stirring.  If  free  sulphuric  acid  is  present 
no  precipitate  appears  until  this  is  satisfied,  when  the  streaks  of 
bitartrate  form  on  the  sides  of  the  vessel.  An  excess  of  reagent 
is  avoided,  and  4  c.c.  are  enough  for  the  maximum  of  4  grams 
of  tartaric  acid.  If  there  is  a  great  deal  of  sulphuric  acid,  a  fine 
precipitate  of  potassium  sulphate  may  appear  before  the  precipi- 
tation of  bitartrate.  The  occurrence  of  a  gelatinous  precipitate 
shows  that  not  enough  citric  acid  was  added,  and  it  is  better  to 
begin  again.  After  standing  twelve  hours  the  precipitate  is  col- 
lected on  a  small  filter,  preferably  a  vacuum  filter,  and  washed 
with  two  or  three  small  portions  of  a  five  per  cent,  solution  of 
potassium  chloride,  then  with  portions  of  alcohol,  successively 
of  50$,  70$,  and  80$  to  90$  strength,  till  the  washings  are  no 
longer  acid  to  litmus.  The  gradual  increase  of  strength  of  alco- 
hol, and  the  previous  use  of  aqueous  solution  of  potassium  chlo- 
ride, are  to  prevent  the  precipitation  of  salts  other  than  the  bi- 
tartrate, such  as  the  gelatinous  phosphates  of  aluminium  and 
iron,  which  may  clog  the  filter,  and  some  of  which  may  interfere 
with  the  titration.  The  filter  and  contents  are  now  transferred 
to  a  beaker,  and  the  bitartrate  estimated  volumetrically  with 
standard  alkali.  Warington  also  gives  a  method  of  washing  the 
precipitate  only  with  a  saturated  solution  of  bitartrate  of  potas- 

1  Pages  977-980  of  the  important  report  on  the  analytical  work  of  Citric 
and  Tartaric  Acid  Manufacture,  1875:  Jour.  Chem.  Sac.,  28,  925-994.  Con- 
tinued, on  Determination  of  Tartaric  Acid  in  Lees,  by  GROSJEAN,  1879:  Jour. 
Chem.  Soc.,  35,  341;  1883:  43,  334;  Jour.  Soc.  Chem.' Indus ,  2,  338. 


492  TARTARIC  ACID. 

slum,  "  till  the  acidity  of  the  drain- water  is  no  greater  than  the 
acidity  of  the  wash- water,"  as  found  volumetrically.  The  drained 
filter  may  be  weighed,  dried,  and  weighed  again,  to  find  the 
amount  of  bitartrate  solution  in  the  drained  filter,  so  that  a  cor- 
rection can  be  made  for  the  bitartrate  retained  in  the  wash- 
liquid.  If  there  be  potassium  sulphate  in  the  precipitate,  it 
will  interfere  with  use  of  this  wash-liquid  by  causing  a  precipi- 
tation of  bitartrate  from  its  solution. 

The  methods  of  estimation  of  the  total  tartaric  acid  in  tartar,, 
argol,  and  lees,  were  summarized  by  WAKINGTON  in  1875  1  es- 
sentially as  follows : 

A. — The  tartaric  acid  of  the  acid  tartrate  of  potassium  is 
found  by  acidimetry,  or  calculated  from  determination  of  the 
potassium  with  platinum  salt  after  calcining.  The  calcium  is 
determined  gravirnetrically  after  calcining,  and  from  this  is  cal- 
culated the  tartaric  acid  of  the  neutral  calcium  tartrate. 

B. — The  calcined  tartar  is  exhausted  with  water,  the  dissolved 
potassium  carbonate  and  the  undissolved  calcium  carbonate  are 
separately  estimated  with  standard  acid  and  alkali,  and  the  tar- 
taric acid  is  calculated  from  both  the  acid  tartrate  of  potassium 
and  the  normal  tartrate  of  calcium. 

C. — The  tartaric  acid  of  bitartrate  is  found  by  acidimetry. 
Another  portion  is  calcined  and  the  total  alkali  (including 
lime)  found  by  alkalimetry.  The  number  of  c.c.  of  alkali  for 
the  bitartrate,  subtracted  from  the  number  of  c.c.  of  corre- 
sponding acid  solution  for  the  ash,  leaves  the  number  of  c.c. 
of  this  acid  required  for  the  lime,  that  is,  the  bases  in  normal 
tartrates. 

D. — The  whole  of  the  tartaric  acid  is  converted  into  normal 
tartrates  by  exact  neutralization  with  soda,  the  whole  evaporated 
to  dry  ness,  calcined,  the  neutralizing  power  of  the  ash  deter- 
mined, and  the  total  tartaric  acid  calculated  therefrom.  It  is  an 
estimation  of  the  carbonates  formed  in  calcining  neutral  salts. 

With  a  pure  tartar  (having  only  the  bitartrate,  the  calcium 
tartrate,  color,  and  sand)  any  one  of  these  methods  will  give 
nearly  correct  results  of  total  tartaric  acid.  Methods  A,  B,  and 
C  give  the  tartaric  acid  in  the  bitartrate,  as  well  as  the  total. 
Calcium  carbonate  in  the  tartar  interferes  with  methods  A  and 
B,  the  carbonate,  if  not  crystalline,  being  acted  upon  by  the  bitar- 
trate in  obtaining  a  solution  in  A.  Calcium  sulphate  also  causes 

1  Jour.  Chem.  Soc.,  28,  959. 


TARTARIC  ACID.  493 

error  in  methods  A  and  B.  But  methods  C  and  D  are  trust- 
worthy in  presence  of  carbonates  and  sulphates  (unless  sulphides 
are  formed  by  ignition,  as  they  will  be  if  nitrogenous  organic 
matter  is  present  with  sulphates).  If  crystallized  carbonate  of 
calcium  is  present,  in  method  0  it  must  be  dissolved  with  the 
tartar  by  adding  a  measured  quantity  of  standard  hydrochloric 
acid,  before  the  acidirnetry,  afterward  deducting  the  standard 
-alkali  needed  to  neutralize  the  hydrochloric  acid.  In  method 
D,  any  calcium  carbonate  must  be  dissolved  by  first  adding 
enough  hydrochloric  acid.  In  any  of  the  four  methods  the  pre- 
sence of  organic  acids  other  than  tartaric,  such  as  malic  acid,  or 
acid  products  of  a  change  in  tartaric  acid,  introduces  error.  Of 
the  four  methods,  Waringtoii  gives  preference  to  method  C, 
though  in  presence  of  carbonates  it  does  not  show  exactly  how 
much  of  the  total  tartaric  acid  is  in  the  bitartrate.  If  there  be 
free  tartaric  acid  there  must  be  more  than  a  corresponding  quan- 
tity of  normal  tartrate,  when  this  method  is  to  be  used.  The 
details  of  method  C  are  given  as  follows 1 :  Five  grains  of  the 
powdered  tartar  are  heated  with  a  little  water,  long  enough  to 
dissolve  any  calcium  carbonate,  and,  if  presence  of  crystallized 
carbonate  be  apprehended,  5  c.c.  of  standard  hydrochloric  acid 
are  added  and  a  covered  beaker  used.  Standard  alkali  is  then 
added  to  the  extent  of  about  three-fourths  of  that  required  for  a 
good  tartar  and  for  the  hydrochloric  acid,  and  the  liquid  is 
brought  to  boiling.  When  cold  the  titration  is  finished.  From 
the  amount  of  alkali  (minus  that  required  by  hydrochloric  acid) 
the  tartaric  acid  in  the  bitartrate  is  stated  (p.  489).  Two  grams  of 
the  powdered  tartar  are  weighed  into  a  platinum  crucible  with  a 
well-fitting  lid ;  the  crucible  is  placed  over  an  argand  burner ; 
heat  is  applied  very  gently  to  dry  the  mass,  and  then  more 
strongly,  till  inflammable  gases  cease  to  be  evolved,  keeping  the 
heat  at  low  redness  or  below.  The  black  ash  is  next  removed 
with  water  to  a  beaker,  and  some  excess — 20  c.c.  if  the  tartar 
is  a  good  one — of  normal  acid  solution  is  added  from  the 
burette,  rinsing  the  crucible  with  the  acid  and  then  with  water. 
After  boiling  and  filtering;  the  excess  of  acid  is  titrated  with 
standard  alkali,  bringing  the  filter  and  its  contents  into  the 
beaker  at  the  last.  From  the  neutralizing  power  of  a  gram  of 
burnt  tartar  is  subtracted  the  acidity  of  a  gram  of  unburnt  tartar, 
both  expressed  in  c.c.  of  standard  alkali,  and  the  difference  is 
the  neutralizing  power  of  the  bases  existing  as  neutral  tartrates, 
then  to  be  calculated  into  tartaric  acid.  One  c.c.  of  normal 

1  Jour.  Chem.  Soc.,  28,  961. 


494  TARTARIC  ACID. 

alkali  is  the  equivalent  of  0.075  gram  of  tartaric  acid  in  normal 
tartrate. 

Warington's  method  of  direct  estimation  of  total  tartaric 
acid  of  argols  and  lees,  known  as  "  the  oxalate  method,"  is  se- 
cure against  the  errors  arising  from  presence  of  carbonates  and 
sulphates,  the  formation  of  sulphides,  and  action  of  vegeta- 
ble acids  not  tartaric.  It  provides  a  removal  of  the  calcium 
by  precipitation  with  potassium  oxalate,  a  precipitation  of  all 
the  tartaric  acid  as  potassium  bitartrate,  and  volumetric  esti- 
mation of  the  latter.1  This  method,  supplemented  by  a  sim- 
ple acidimetry  to  show  nearly  the  quantity  of  acid  in  bitar- 
trate, may  be  adapted  to  various  troublesome  analyses  of  adul- 
terated cream  of  tartar. —  A  quantity  of  the  material,  in  pow- 
der, sufficient  to  contain  about  2  grams  of  tartaric  acid,  is  placed 
in  a  small  beaker,  covered  with  water,  and  heated  on  the  water- 
bath  till  thoroughly  softened.  Sufficient  solution  of  potassium 
oxalate  (of  about  25$  strength)  to  unite  with  all  the  calcium 
and  give  an  excess  of  about  \\  gram  of  oxalate  is  then  added, 
and  the  heat  maintained,  with  frequent  stirring,  for  half  an  hour. 
The  solution,  if  strongly  acid,  as  it  usually  will  be,  is  now  nearly 
neutralized  by  carefully  adding  solution  of  soda  by  drops,  the 
reaction  being  left  distinctly  acid,  and  digestion  on  the  water- 
bath  continued  half  an  hour.  The  volume  of  liquid  is  now 
made  about  30  c.c.,  and  the  whole  filtered  (while  hot)  with  a 
vacuum  filter.  Mr.  Grosjean  uses  Cassamajor's  filter,2  in  an  or- 
dinary funnel,  and  very  little  vacuum.  The  residue  is  washed 
ten  times,  each  with  2  or  3  c.c.  of  water,  and  the  washings  sepa- 
rately concentrated  to  bring  the  wrhole  filtered  liquid  to  50  c.c. 
Five  grams  of  potassium  chloride  are  now  added  and  dissolved, 
and  the  solution  treated,  while  cold,  with  a  quantity  of  citric 
acid  equal  to,  or  a  little  greater  than,  the  quantity  of  tartaric 
acid  to  be  found.  The  liquid  is  stirred  continuously  for  ten 
minutes  and  set  aside  half  an  hour,  then  collected  on  a  vacuum 
filter  and  washed  twice  with  a  five  per  cent,  solution  of  potas- 

2  WARINGTON,  ibid,,  p.  973.  GROSJEAN,  1879:  35,  341:  "  This  method, 
with  individual  variations,  is,  I  believe,  now  exclusive!}  employed  in  fixing  the 
value  of  lees  and  inferior  argol  sold  in  the  London  market."  A  similar  plan, 
of  simpler  execution,  with  use  of  carbonate  of  potassium  (instead  of  oxalate)  to 
precipitate  calcium  and  bring  all  the  tartaric  acid  into  solution  as  normal  salt, 
and  with  acetic  acid  and  alcohol  as  precipitants,  is  given  by  GOLDENBERG  and 
others,  1883:  Zeitsch.  anal.  Chem.,  22,  270;  Chem.  News,  48;  New  Rcm.,  12, 
242.  The  precipitation  by  potassium  carbonate  has  been  employed  gravimet- 
rically  for  the  calcium. 

2 1875:  Am.  Chem.,  5,  438;  Chem.  News,  22,  45. 


TARTAR1C  ACID.  495 

slum  chloride,  then  twice  with  fifty  per  cent,  alcohol,  and  lastly 
with  strong  alcohol  till  the  washings  are  no  longer  acid  to  lit- 
mus. The  whole  washing  may  be  done  with  a  five  per  cent, 
solution  of  potassium  chloride  carefully  saturated  with  potassium 
bitartrate,  continued  till  the  washings  neutralize  no  more  stand- 
ard alkali  than  the  wash-liquid,  in  the  end  making  a  correction 
for  the  acid  in  the  liquid  remaining  in  the  filter.  The  pre- 
cipitate and  filter,  transferred  to  a  beaker,  are  titrated  with 
standard  alkali  (p.  489).  If  by  inattention  too  much  reagent  oxa- 
late  of  potassium  have  been  used,  acid  oxalate  of  potassium  may 
be  crystallized  in  the  precipitate.  In  the  analysis  of  good  tartar 
by  this  method  the  filtering  of  the  oxalate  precipitate  may  be 
omitted,  and  the  citric  acid  added  to  the  cold  neutralized  mix- 
ture. In  this  case  the  oxalate  of  calcium,  vegetable  matter, 
and  sand,  in  the  bitartrate  precipitate,  do  not  affect  the  titration. 

In  estimating  tartaric  acid  in  Fruit  Juices,  as  a  general 
method  providing  for  the  other  fruit  acids,  FLEISCHER  *  directs 
as  follows :  Filter  clear,  if  necessary  by  the  addition  of  alcohol, 
and  washing  on  the  filter  with  alcohol  or  hot  water.  The  liquid 
is  hilly  precipitated  with  lead  acetate  solution  ;  the  precipitate 
drained  on  the  filter  and  washed  with  aqueous  alcohol,  and  then 
treated  thoroughly  with  excess  of  ammonium  hydrate  (free  from 
carbonate)  and  filtered.  The  residue  contains  lead  salts  of  any 
phosphoric,  sulphuric,  and  oxalic  acids  of  the  fruit ;  while  tartaric, 
citric,  and  malic  acids  are  in  the  filtrate.  The  latter  is  treated 
with  some  excess  of  ammonium  sulphide,  then  acidulated  with 
acetic  acid,  and  filtered.  This  filtrate,  boiled  to  expel  hydrogen 
sulphide,  is  treated  with  potassium  acetate  and  alcohol,  as  above 
directed,  for  estimation  of  the  tartaric  acid  by  acidimetry  of  the 
precipitate.  The  filtrate  contains  the  citric  and  malic  acids, 
which  are  now  precipitated  by  addition  of  calcium  chloride^  am- 
monium hydrate,  and  a  little  alcohol.  The  precipitate  of  citrate 
and  malate  may  be  freed  from  malate  by  washing  it  with  boiling 
solution  of  calcium  hydrate.  The  citrate  may  be  dissolved  in 
acetic  acid,  and  precipitated  by  lead  acetate,  to  weigh  as  lead 
citrate. 

f. — Tartaric  acid,  in  pure  water  solution,   has  percentages 
corresponding  to  specific  gravities,  as  follows :  * 

11874:  Zeitsch.  anal.  Chem.,  13,  328,  in  full  from  Archiv  d.  Pharm.  [3]  5, 
97;  Amer.  Chem.,  6,  154;  abstracted  in  Jour.  Chem.  Soc.,  27,  1181,  and  in 
Pro.  Am.  Phar.  Assoe.,  1875,  380.  See  also  A.  II.  ALLEN:  Phar.  Jour.  Trans. 
[3]  6,  6;  Jahresb.  d.  Chemie,  1875,  969. 

*SCHIFF.    See  also  GERLACH:  Zeifsch.  an.  Chem.,  viii.  (1869)  295. 


496  TARTARIC  ACID. 

1.0167  sp.  gr.  at  15°  C 3.67  per  cent. 

1.0337      "       "      "    7.33       " 

1.0511      "       "      " 11.00       " 

1.0690      "       "      " 14.66       " 

1.1069      "       "      "    22.00       " 

1.1654      "        "      "    33.00       " 

g. — Impurities. — Tartaric  acid  is  liable  to  contain  a  trace  of 
Sulphuric  acid,  from  the  manufacture,  but  more  than  slight 
traces  of  this  impurity  render  the  crystals  deliquescent.  Minute 
traces  of  calcium  sulphate  and  of  lead  tartrate  may  also  be  left 
from  manufacture.  Falsifications  with  alum,  borax,  and  sodium 
nitrate  are  mentioned.  The  powder  is  more  liable  to  adultera- 
tions. The  solubility  in  least  quantities  of  alcohol  (p.  486* 
serves  as  a  test  for  absence  of  saline  impurities 

THE  ACID  TAKTKATE  OF  POTASSIUM.  Bitartrate  of  Potassium. 
Cream  of  Tartar.  Tartar.  J)er  gereinigte  Weinstein. — Purity 
and  strength  of  normal  tartars. — Manufactured  from  the  Argols 
and  to  a  less  extent  from  the  Lees  of  grape- wine  fermentation, 
bv  dissolving  out  with  hot  water  and  crystallizing  the  solution, 
the  operation  being  repeated  several  times.  Argols  and  lees 
contain  calcium  tartrate,  and  smaller  proportions  of  aluminium, 
iron,  and  magnesium  oxides  and  salts,  phosphates,  sand,  and 
vegetable  matter.  They  also  frequently  contain  "  plaster," 
chiefly  calcium  sulphate,  and  sometimes  including  calcium  car- 
bonate and  Spanish  earth.  The  quantity  of  calcium  tartrate 
varies  from  6$  to  20$  *  in  lees,  from  5$  to  10#  or  15# 2  in  argols,  and 
from  2$  to  9$  or  10$  3  in  legitimate  tartars  of  the  market.  The 
cream  of  tartar  of  the  U.  S.  Ph.  of  1880  (1882)  is  required'  to 
bear  a  limit  test  for  calcium,  defined  as  proof  of  "  absence  of 
more  than  6  per  cent,  of  tartrate  of  calcium."  The  limit  test  of 
the  tartar  of  the  German  Pharmacopoeia  is  very  close  in  its  con- 
ditions of  time  and  concentration,  and  is  defined  by  the  experi- 
ments of  BiLTz4  as  excluding  calcium  tartrate  above  \%.  The 
article  "  kalkfreier  Weinstein"  (lime-free  tartar)  is  mentioned  as 

1  WARINGTON,  1875:  Jour.  Chem.  Soc.,  28,  951. 

2  General  report  of  New  York  importers. 

3  ALLEN,  1880:  The  Analyst,  5,  116,  found  by  experiments  with  mixtures 
of  pure  potassium  bitartrate  and  excess  of  pure  calcium  tartrate  that  the  quan- 
tities of  calcium  tartrate  left  after  a  single  crystallization  of  nitrates  from  boil- 
ing water  solutions  varied,  in  proportion  to  the  water  used  (25  to  75  parts), 
from  5.83  per  cent,  to  9.02  per  cent.     WARINGTON,  Jour.  Chem.  Soc.,  28,  958, 
gives  a  general  statement  of  the  amounts  of  acid  in  calcium  tartrate,  equivalent 
to  a  range  of  2  to  8.8  per  cent,  of  calcium  tartrate. 

4  Notizen  zur  Pharm.  German.,  1878,  p.  251. 


ACID  TART  RATE  OF  POTASSIUM.  497 

being  "  as  far  as  possible  free  from  calcium."  Undoubtedly 
tartars  of  almost  any  required  degree  of  purity  can  be  obtained, 
upon  order,  from  certain  manufacturers,  while  very  little  tartar 
with  less  than  2$  calcium  tartrate  appears  to  be  in  use  in  Eu- 
rope or  in  this  country.  Tartar  with  not  over  5$  or  at  most 
6$  calcium  tartrate,  if  not  otherwise  imperfect,  is  to  be  accepted 
at  present  as  a  good  article  for  ordinary  uses.  Ten  per  cent,  of 
calcium  tartrate  must  be  about  the  utmost  quantity  in  legitimate 
tartars,  those,  however  poorly  or  cheaply  manufactured,  not  adul- 
terated by  addition.  "  Crystallized  tartar  " — that  in  larger  crystals, 
subsiding  in  the  crystallizing  liquid — does  not  very  much  differ  in 
purity  from  the  small  crystals,  the  "  cream  "  of  the  liquid. 

The  strength  of  tartars  is  their  acidity  due  to  acid  tar- 
trate, and  is  stated  in  parts  per  cent,  of  this  salt.  According  to 
WARiNGTON2  the  best  tartars  of  South  Italy  have  from  91.0$  to 
94.7$  of  bitartrate  ;  good  ordinary  Italian  tartars,  87.8$  to  90.3$  ; 
and  Vinaccia  tartars,  from  79.$$  to  85.3$.  The  first  named  of 
these,  termed  Venetian  tartars,  are  the  best  o4'  those  not  pre- 
sented as  lime-free  tartars.  The  French  tartars  do  not  equal  the 
Venetian. 

The  adulterations  common  in  cream  of  tartar  (ground  or  in 
crystals)  are  terra  alba,  chalk,  alum,  and  tartrate  of  calcium. 
Tartaric  acid,  acid  phosphate  of  calcium,  starch  or  flour,  and 
barium  sulphate  have  been  found.  .  Two  lots  (with  alum  or  an 
inert  adulterant)  adulterated  with  oxalic  acid  were  found  in 
1886  in  New  York  Of  27  suspected  samples,  the  New  York 
State  Board  of  Health,  in  1882,  found  16  to  be  adulterated,  and 
8  to  contain  3.27$  to  93$  of  terra  alba,  of  which  5  samples  had 
over  70$.  The  tartrate  of  calcium  did  not  exceed  10.39$  in  any 
case.3  Large  proportions  of  calcium  compounds  have  been  re- 
ported by  various  analysts,  and  reported  in  some  cases  as  calcium 
tartrate.  Calcium  carbonate  is  so  promptly  changed  to  tartrate 
in  solution  of  the  bitartrate  that  it  is  not  unlikely  that  an  addi- 
tion of  some  form  of  calcium  carbonate  has  repeatedly  given  rise 
to  an  analyst's  report  of  much  calcium  tartrate.4  When  the  addi- 

1  Hager's  Pharm.  Praxis,  II.  279  (1878). 

2  By  calculation  from  the  figures  in  Jour.  Chem.  Soc. ,  28,  958. 

3  E.  G.  LOVE,  1882 :  Sanitary  Engineer,  March  30,  1882,  p.  iv. ;  The  Ana- 
lyst, 7.  142. 

4C.  G.  STONE,  Univ.  Mich  ,  1877:  New  Rem.,  6,  274— of  12  samples,  6  had 
from  6.1  percent,  to  8  per  cent,  calcium  tartrate,  and  6  did  not  have  over 
6  per  cent,  of  this  salt;  2  had  61  and  64  per  ce"nt.  of  calcium  sulphate. 

LONGWELL,  Univ.  Mich.,  1882:  Phys.  and  Surg.,  4,  404 — of  11  sample:-, 
highest  calcium  as  tartrate,  7.8  per  cent.;  4  samples,  calcium  as  carbonate, 
49.5  to  63.4  per  cent.  RIEGER,  Univ.  Mich.,  1883,  unpublished — of 
4  stated  with  41.5  to  68.1  per  cent,  calcium  as  tartrate. 


498  TARTARIC  ACID. 

tion  is  calcium  sulphate,  the  sulphuric  acid  would  remain  and 
would  seldom  fail  to  be  reported  as  sulphate  of  one  base  or  the 
other,  but  the  acid  of  the  carbonate  may  escape  unnoticed  in 
treating  with  water.  Tartrate  of  calcium,  inert  in  ordinary  uses 
of  cream  of  tartar,  is  a  by-product  of  value  for  production  of 
tartaric  acid.  That  it  is  added  to  tartars,  in  proportions  several 
times  greater  than  they  can  derive  from  the  argol,  does  not  ap- 
pear to  be  established  by  any  evidence  at  the  author's  hand. 
The  composition  of  crystallized  Tartrate  of  Calcium  is 
CaC4H4O6 .  4H2O.  It  loses  about  17$  of  its  weight  on  the 
water-bath,  and  nearly  all  its  water  at  200°  C.,  but  it  can  be  esti- 
mated as  carbonate  after  igniting  and  treating  with  ammonium 
carbonate.  It  is  soluble  in  about  6000  parts  of  water  at  15°  C., 
and  in  about  350  parts  of  boiling  water.  It  is  somewhat  soluble 
in  ordinary  free  acids,  in  solution  of  the  bitartrate  of  potassium, 
in  solution  of  ammonium  chloride,  and  in  cold  potassium  or 
sodium  hydrate  solution. 

Determination  of  the  Purity  and  Strength  of  Cream  of 
Tartar. — Tests  for  sulphates,  chlorides,  salts  of  heavy  metals, 
and  the  six  per  cent,  limit  of  calcium  tartrate  are  given  in  the 
TJ.  S.  Pharmacopoeia.  Free  tartaric  acid  can  be  tested  for,  and 
estimated,  by  treating  the  line  powder  with  alcohol,  evaporating 
the  alcohol  from  the  filtrate,  testing  for  acid,  and,  if  found,  esti- 
mating it  volumetrically.  In  a  nitric  acid  solution  of  the  tartar 
phosphoric  acid  may  be  tested  for  with  molybdate.  If  sulphates 
are  present,  the  ash,  or  the  thoroughly-charred  mass,  in  hydro- 
chloric acid  solution,  should  be  tested  for  aluminium,  which 
may  be  done  (in  absence  of  phosphate)  by  adding  ammonium 
chloride  and  a  slight  excess  of  ammonia- water.1  If  aluminium  be 
found  in  any  considerable  quantity,  ammonia  may  be  tested  for, 
as  further  evidence  of  alum,  terra  alba,  or  chalk,  or  other 
earthy  addition  will  be  left  undissolved  after  treatment  of  the 
powdered  tartar  with  warm  potassium  hydrate  solution  (which, 
not  too  hot,  dissolves  calcium  tartrate).  The  residue,  filtered 
out  and  washed,  is  examined  for  carbonates,  sulphates,  calcium, 
barium,  silica,  etc.  Then  the  operation  may  be  made  a  quanti- 
tative one,  and  the  collected  residue  washed,  dried,  and  weighed. 
But  in  case  of  terra  alba  (calcium  sulphate)  alcohol  should  be  add- 
ed before  filtering,  and  dilute  alcohol  used  in  washing.  Starchy 
matters  will  be  shown,  after  heating  in  water,  by  the  iodine  test. 
Now,  in  absence  of  alum,  free  tartaric  acid,  acid  phosphate,  or 
other  foreign  substance  that  can  neutralize  an  alkali,  the  strength 

'In  presence  of  the  tartrate  ammonia  does  not  fully  precipitate  alumi- 
nium. 


A  CID  TA  R  TRA  TE  OF  PO  TA  SSIUM.  499 

of  the  tartar,  in  percentage  of  hi 'tart rate  of  potassium^  may  be 
found  by  acidimetry  (p.  489).  Weighing  out  4.7  grams  of  the 
powder,  sixty  to  eighty  c.c.  of  hot  water  are  added,  and  normal 
solution  of  alkali  run  in  from  the  burette,  with  stirring  and 
heat  if  necessary  to  dissolve  the  tartar  before  the  titration  is 
completed,  until  the  neutral  point  is  indicated  by  litmus  or  by 
phenol-phthaleiri.  The  number  of  c.c.  X  4  =  the  number  per 
cent,  of  bitartrate.  One  c.c.  of  normal  alkali  equals  0.188  gram 
of  bitartrate.  Should  the  percentage  of  real  tartar  be  too  low, 
it  will  be  the  more  necessary  to  analyze  the  neutral  substances 
making  up  the  complementary  percentage. 

If  further  work  be  required,  in  most  cases  the  calcium  is 
next  to  be  determined.  In  absence  of  alum  and  of  earthy  ad- 
ditions, the  total  calcium  may  be  estimated  (without  calcining 
the  tartar)  as  follows:  Five  grams  of  the  tartar  and  2  grams 
of  anhydrous  sodium  carbonate  are  boiled  with  water  and  well 
digested,  the  mixture  filtered,  the  residue  washed,  dried,  and 
weighed  as  calcium  carbonate. 

CaCO3  :  CaC4H4O6.4H2O::l  :  2.6. 
Or     CaCOg  :  CaC4H4O6 : :  1  :  1.88. 

The  percentage  of  crystallized  calcium  tartrate,  added  to  that 
of  potassium  bitartrate,  in  a  legitimate  tartar,  should  give  a  sum 
not  far  from  100. 

When  earthy  additions  or  alum  have  been  found  it  is  better 
to  ignite  a  portion  of  the  tartar.  Two  or  three  grams,  weighed, 
are  dried  in  a  covered  crucible,  and  gradually  ignited  until 
vapors  cease  to  rise,  when  small  portions  of  ammonium  nitrate 
(or  potassium  nitrate)  are  added,  until  by  the  continued  calcina- 
tion a  white  ash  is  obtained.  This  is  cooled,  exhausted  with 
hot  water,  washed,  with  the  rinsings,  on  a  filter,  and  the  residue 
titrated  as  follows :  Both  the  filter  and  the  crucible  are  placed 
in  a  beaker,  an  excess  of  standard  hydrochloric  acid  added  from 
a  burette,  the  liquid  heated  and  brought  back  to  the  neutral 
point  with  standard  alkali.  Each  c.c.  of  normal  acid  solution 
used  (after  deduction  of  the  alkali  used)  represents  0.050  gram 
of  calcium  carbonate,  or  0.130  gram  of  crystallized  calcium 
tartrate,  or  0.094  gram  of  anhydrous  calcium  tartrate.  When 
calcium  sulphate  is  present,  some  reduction  to  sulphide  will  oc- 
cur in  the  ignition,  and  a  corresponding  portion  of  calcium  of 
reduced  sulphate  will  be  included  in  the  estimation. — If  there 
be  a  residue  of  the  ash  insoluble  in  hydrochloric  acid  (terra  alba, 
silicious  matter),  it  may  be  washed,  dried  and  weighed,  and  after- 
ward subjected  to  analysis. 


500  TARTARIC  ACID. 

If  alum  is  to  be  estimated,  in  absence  of  other  sulphates,  it 
may  be  easily  done  by  a  gravimetric  estimation  of  sulphuric 
acid  as  barium  salt,  precipitating  in  a  strongly  acid  solution, 
and  igniting  the  precipitate  in  the  usual  way. 

To  obtain  the  quantity  of  calcium  tartrate  when  other  cal- 
cium salts  are  present,  the  powdered  tartar  may  be  treated  with 
warm  potassium  hydrate  solution  (as  directed  on  p.  498),  adding 
alcohol  if  there  is  sulphate,  washing  the  residue  on  a  filter, 
evaporating  the  filtrate,  first  neutralized  with  hydrochloric  acid, 
and  precipitating  with  oxalate  of  ammonium  in  presence  of  a 
little  free  acetic  acid.1  The  precipitate  is  weighed  as  carbonate, 
after  ignition.  A  more  complete  analysis  may  be  conducted  by 
determining  the  total  tartaric  acid  by  Warington's  direct  method 
(p.  494),  the  acidity  due  to  acid  tartrate  by  simple  acidimetry,  the 
total  calcium  soluble  from  the  ash  by  hydrochloric  acid,  and 
the  ash  not  calcium  carbonate.  Unless  irregular  constituents 
are  present,  the  tartaric  acid  in  excess  of  that  in  the  acid  tartrate 
may  be  calculated  into  normal  tartrate  of  calcium,  and  any  excess 
of  calcium  beyond  that  in  the  calcinm  tartrate  calculated  into 
carbonate  or  sulphate,  or  as  the  qualitative  examination  indicates. 

BAKING-POWDERS. — These  have  so  far  been  presented  to  the 
public  either  as  cream  of  tartar  baking-powders,  or  without 
statement  of  their  constituents,  or  as  acid  phosphate  powders 
(Horsford's).  They  consist  of  sodium  bicarbonate  with  an  acidi- 
fying agent,  potassium  bitartrate,  or  alum,  or  tartaric  acid,  or 
acid  phosphate  of  calcium.  Ordinary  carbonate  of  ammonium 
has  been  used,  alone,  as  a  baking-powder,  and  more  used  for  a 
part  with  acidifying  agents.  A  proportion  of  starch  or  flour, 
as  "  filling,"  is  found  in  nearly  all  baking-powders,  and  is  neces- 
sary to  the  permanence  of  tartar  and  tartaric  acid  powders. 
From  13  to  18  per  cent,  of  starch  is  not  too  much  for  the  per- 
manence of  a  cream  of  tartar  baking-powder,  but  filling  beyond 
20  per  cent,  must  be  held  an  unquestionable  dilution.51  There 

1  The  precipitation  of  calcium  from  tartars,  as  an  oxalate,  is  in  most  cases 
more  trustworthy  if  done  in  the  presence  of  a  little  free  acetic  acid.  The  solu- 
tion should  not  be  very  dilute,  and  twelve  to  twenty-four  hours  should  be  given 
to  the  precipitation. 

*  Dr.  B.  G.  LOVE,  acting  for  the  New  York  State  Board  of  Health,  in  1882 
(Sanitary  Engineer,  March  30;  The  Analyst,  7,  142)  found,  of  84  baking-pow- 
ders upon  sale,  49  were  cream  of  tartar  powders,  3  were  tartaric  acid  powders, 
20  were  alum  powders,  3  were  acid  phosphate  powders,  8  contained  both  cream, 
of  tartar  and  alum,  and  1  had  alum  with  acid  phosphate.  Flour  or  starch  was 
found  in  all  but  11.  Ammonia  was  found  in  35.  [The  alum  reported  in  29  of 
them  was  doubtless  ammonia  alum.]  Eight  were  reported  adulterated — six 
with  terra  alba,  one  with  tartrate  of  lime  (in  the  tartar),  and  one  with  insoluble 
calcium  phosphate. 


BA  KING-PO  WDERS.  50 1 

has  been  dispute  as  to  the  injurious  effect  of  alum  baking-pow- 
ders, but,  at  all  events,  they  are  seldom  if  ever  sold  to  the  public 
with  any  statement  or  admission  that  they  contain  alum. 

The  proportion  of  carbon  dioxide  extricated  on  boiling  a 
baking-powder  with  water  is  termed  its  "  strength,"  and  is  stated 
in  percentage  of  weight,  or  in  cubic  inches  (at  60°  F.,  30  in.  bar.) 
from  an  avoirdupois  ounce.  In  the  case  of  a  cream  of  tartar 
powder  we  have  : 

JSTaHC03  +  KHC4H406  =  KNa  C4H4O6  +  CO2  +  H0O 

84         +188  =272  44 

30.38$      +69.12$       =:  100.00$  16.17$ 

At  60°  F.  and  30  inches  pressure  46.26  grains  of  carbon  dioxide 
measure  100  cubic  inches  ;  therefore  16.17  grains  measure  34.09 
cubic  inches.  That  is  to  say,  100  grains,  of  a  mixture  30.88$  ab- 
solute bicarbonate  and  69.12$  absolute  bitartrate,  will  furnish 
16.17  grains  or  34.18  cubic  inches  of  the  gas.  And  1  av.  oz.  of 
the  same  chemically  pure  mixture  will  furnish  149.54  cubic 
inches  of  the  gas.  If  we  have  a  baking-powder  holding,  for  ex- 
ample, 84$  of  the  equivalent  soda  and  tartar,  then  no  more  than 
84$  of  149.54  cubic  inches  of  gas  can  be  obtained  from  one  av. 
ounce.  Less  than  the  theoretic  yield  of  gas  may  be  obtained 
(1st)  because  reaction  of  the  tartar  upon  the  soda  may  have  trans- 
pired in  the  mixture  (not  fully  dry),  (2d)  because  of  deficient 
quality  of  the  soda,  or  of  the  tartar,  or  of  both,  and  (3d)  because 
of  wrong  proportions  of  tartar  to  soda.  With  the  proportions  of 
filling  before  mentioned,  cream  of  tartar  baking-powders,  in 
moderately  dry  air,  will  not  appreciably  lose  carbon  dioxide. 
Powders  made  with  tartaric  acid  lose  gas  more  readily,  and  the 
same  has  been  stated  of  the  acid  phosphate  powders.1 

The  examination  of  baking -powders  should  begin  with  a 
qualitative  analysis.  In  answer  to  special  questions,  tests  may 
be  briefly  made  for  sulphates,  ammonia,  aluminium,  residue  in- 
soluble in  boiling  water  (besides  gelatinized  starch),  and  calcium 
in  watery  solution,  as  well  as  in  acid  solution  of  any  residue  not 
dissolved  by  water.  Phosphate  may  be  tested  for  in  acid  solu- 
tion by  molybdate.  Free  tartaric  acid  would  be  found  in  a  fil- 
tered alcoholic  solution.  The  reaction  to  test-paper  after  boiling 
thoroughly  in  water  is  of  first  importance.  This  is  neutral  in 

1  In  1881  Dr.  E.  G.  LOVE  reported  the  yield  of  gas  in  cubic  content  from 
sixteen  different  brands  of  American  Baking-Powders  (The  Analyst,  6,  65). 
From  one  ounce  the  highest  yield  was  127.4  cubic  inches  of  gas,  and  the  lowest 
was  75.0  cubic  inches,  except  one  (old)  which  was  32.7  cubic  inches.  Ten  fur- 
nished over  100,  and  four  over  120,  cubic  inches  of  gas. 


502  TARTARIC  ACID. 

well  made  powders  :  it  is  seldom  found  to  be  acid,  but  is  some- 
times found  to  be  alkaline. 

In  the  estimation  of  the  carbon  dioxide,  only  that  quantity  of 
gas  which  is  liberated  by  water,  with  warming  at  the  end  to 
boiling  point,  and  without  adding  an  acid,  can  be  counted  as 
"  strength."  However,  if  an  alkaline  reaction  have  not  been 
found  after  boiling  with  water,  the  use  of  an  acid  to  liberate  the 
gas  will  introduce  no  inaccuracy  in  finding  the  "  strength."  The 
writer  prefers  to  estimate  the  carbon  dioxide  by  the  method  of 
increase  of  weight  of  absorption  tubes,  using  water  without  acid 
and  with  gentle  heat  finally  to  boiling,  to  liberate  just  the  gas 
counted  as  strength.  Methods  by  diminution  of  weight  due  to 
escape  of  the  dried  gas  seldom  give  trustworthy  results,  at  least  in 
the  writer's  observation.  If  a  Scheibler's  apparatus  for  measur- 
ing the  volume  of  the  gas  be  at  hand,  it  may  be  used,  with  addi- 
tion of  hydrochloric  acid  in  the  usual  way ;  but  if  it  be  a  powder 
showing  an  alkaline  reaction  after  boiling  with  water,  a  correction 
must  be  made,  from  results  of  alkalimetry  after  boiling  with 
water,  for  statement  of  the  "  strength." 

With  a  true  cream  of  tartar  baking-powder  (free  from  alum) 
a  most  serviceable  valuation  can  be  made  by  a  simple  alkalimetry 
of  the  ash  (A\  together  with  alkalimetry  of  the  liquid  obtained 
by  boiling  the  baking  powder  with  water  (B)  in  case  this  liquid 
be  alkaline,  or  acidirnetry  of  the  same  (O)  in  case  it  be  found 
acidulous.  Using  decinormal  volumetric  solutions  of  acid  and 
alkali, 

In  A,  1  c.c.  of  acid  =  0.0136  gm.  soda  tartar 

(Na  HCO3  +  KHC4H4O6) 

In  B,  1  c.c.  of  acid  =  0.0084  gm.  excess  of  soda  (NaHCO3) 
In  O,  1  c.c.  alkali    =0.0188  gm.  excess  of  tartar  (KHC4H4O6) 

If  the  powder  be  found  to  have  an  excess  of  alkali,  to  estimate 
this  weigh  0.840  gram,  boil  with  water,  add  from  the  burette 
some  excess  of  decinormal  solution  of  acid,  boil  again,  and  bring 
back  to  the  neutral  point  by  adding  decinormal  alkali  from  a 
burette.  The  number  of  c.c.  (B}  of  decinormal  acid,  beyond 
that  taken  to  neutralize  the  decinormal  alkali  used,  equals  the 
number  per  cent,  of  excess  of  sodium  bicarbonate  (that  is,  the 
number  of  parts  of  such  excess  in  100  parts  of  baking-powder). 
If  the  baking-powder  have  an  excess  of  acid,  weigh  1.880  gram, 
boil,  and  add  from  the  burette  decinormal  solution  of  alkali  to 
neutralize.  Then  (as  above)  c.c.  (C)  =  parts  excess  of  potas- 
sium bitartrate  in  100  parts  baking  powder.  Whether  the 
boiled  liquid  have  been  found  alkaline,  acid,  or  neutral,  for  the 


BA  KING-PO  WDERS.  503 

•ash  weigh  1.360  gram  of  the  baking-powder,  heat  it  in  a  covered 
capsule  very  gradually,  so  as  not  to  permit  the  puffy  mass  to 
reach  the  cover,  at  last  continuing  a  red  heat  for  fifteen  or 
twenty  minutes  after  the  vapors  have  ceased  to  rise.  Cool  the 
•capsule,  boil  it  (cover  and  all)  with  a  little  water,  in  a  beaker, 
gently  rubbing  up  the  black  ash  with  a  glass  rod.  If  no  separa- 
tion of  calcium  of  the  tartar  is  to  be  undertaken,  the  decinormal 
acid  may  now  be  added  at  once,  in  excess,  the  mixture  boiled, 
and  (being  acid  after  boiling)  filtered  and  washed  till  the  wash- 
ings do  not  change  blue  litmus-paper.  The  filtrate  and  washings 
are  titrated  back  to  the  neutral  point  with  decinormal  alkali.  If 
the  powder  have  been  found  neutral  after  boiling  at  the  begin- 
ning, the  c.c.  of  decinormal  acid,  minus  the  c.c.  of  decinor- 
mal alkali,  =  the  parts  of  absolute  equivalent-soda-tartar 
CNaHCO3  +  KIlC4H4O6)  in  100  parts  of  the  baking-powder. 
If  the  powder  have  shown  an  excess  of  alkali,  then  |f  (  =  Vi6  — 
161.9$)  of  the  number  of  c.c.  B,  found  as  above,  is  to  be  deduct- 
ed from  the  number  of  c.c.  required  for  the  ash.  If  the  powder 
have  shown  an  excess  of  acid,  deduct  f ^  ( =  ff  £  =  72.34$)  of 
the  number  of  c.c.  C  (decinormal  alkali)  from  the  number  of  c.c. 
of  decinormal  acid  used  for  the  ash.  In  each  of  these  cases  the 
remainder  =  parts  of  equivalent  soda- tartar  in  100  parts  of 
baking-powder.  Then  the  per  cent,  of  sodium  bicarbonate  in  the 
baking-powder  is  30.88$  (p.  501)  of  the  per  cent,  of  equivalent- 
soda-tartar,  plus  the  per  cent,  of  excess  of  "  soda,"  if  any.  And 
the  total  per  cent,  of  potassium  bitartrate  is  69.12$  of  the  per 
cent,  of  soda  tartar,  -J-  any  per  cent,  of  excess  of  "  tartar " 
found. 

If  it  be  desirable — from  the  qualitative  indications^ — to  esti- 
mate the  calcium  tartrate  in  the  alkalimetry  of  the  ash,  the  black 
ash  from  the  capsule  must  be  exhausted  and  washed  with  boiling 
water  until  the  washings  no  longer  show  an  alkaline  reaction — 
to  litmus  or  to  phenol-phthalein — when  the  total  filtrate  is  ti- 
trated, as  above  directed.  The  residue,  filter,  capsule,  and  all,  is 
now  digested,  cold,  with  standard  hydrochloric  acid,  or,  if  there 
be  not  a  large  quantity  of  calcium,  digested  warm  with  standard 
sulphuric  acid  and  sufficient  water,  filtered,  washed  (compare  on 
p.  499),  and  the  filtrate  titrated  back  for  alkalimetry  of  the  cal- 
cium carbonate,  referred  to  tartrate.  1  c.c.  of  decinormal  solu- 
tion of  acid,  neutralized  by  the  washed  ash,  indicates  0.0130  gram 
of  crystallized  (or  0.0094  gram  of  anhydrous)  calcium  tartrate 
(p.  498).  The  quantity  of  calcium  tartrate  found  is  to  be  added 
to  the  total  quantity  of  potassium  bitartrate  found  ($  of  latter  -=- 
100  X  1.36),  the  sum  being  the  quantity  of  cream  of  tartar 


504  TEAS   OF  COMMERCE. 

lime-free)  used  in  the  1.36  gram  of  baking-powder.  Statements 
are  then  made  of  the  percentage  of  cream  of  tartar  in  the  baking- 
powder,  and  of  the  percentage  of  calcium  tartrate  in  the  cream  of 
tartar.  These  percentages  may  be  calculated,  directly  from 
numbers  of  c.c.  found,  as  follows :  1.36  gram  baking-powder 
having  been  calcined,  95.6$  of  the  c.c.  for  CaCO3  (m)  -)-  %  of 
total  KHC4H4O6  previously  found  —  %  (n)  cream  of  tartar  (not 
lime-free)  in  the  baking-powder.  And  m  -=-  n  =  %  of  crystal- 
lized calcium  tartrate  in  the  cream  of  tartar  used. — The  calcium 
tartrate  may  be  determined  gravimetrically,  as  given  on  page  500, 
or  on  page  499,  the  precipitate  of  carbonate  being  ignited  to  re- 
move starch,  if  necessary. 

For  estimation  of  constituents  of  baking-powders,  used  also 
in  adulteration  of  cream  of  tartar,  see  pp.  498  to  500. 

TEAS  OF  COMMERCE.— The  prepared  leaf  of  the 
Thea,  native  to  the  Himalayas  and  Assam,  long  cultivated  in 
China  and  Japan,  and  now  cultivated  in  India.  The  kinds  of 
tea  known  in  commerce  are  distinguished  in  the  first  place  by  the 
age  of  the  leaf  employed.  Thus,  the  youngest  leaf  is  found  in 
"flowery  pekoe";  the  next  in  age,  successively  in  "orange 
pekoe,"  u  pekoe,"  "  souchong,"  and  "  bohea."  Without  distinc- 
tion of  the  age  of  the  leaf,  "  green  teas  "  differ  from  "  black 
teas  "  according  to  the  mode  of  preparation.  The  treatment  of 
the  fresh  tea  leaf  in  manufacture  of  tea  is  always  an  elaborate 
operation,  and  includes  exposure  to  a  roasting  temperature.  For 
black  teas  the  leaves  are  withered  a  little,  rolled  to  liberate  the 
juices,  left  in  balls  for  the  proper  extent  of  fermentation,  then 
sun-dried  and  subjected  to  a  careful  firing  in  a  furnace.  For 
green  teas  the  fresh  leaves  are  first  withered  in  hot  pans,  then 
rolled  to  free  the  juices,  slightly  roasted  in  the  pans,  sweated  in 
bags,  and  returned  to  the  pans  for  a  final  slow  roasting,  with 
stirring,  for  eight  or  nine  hours,  beginning  at  the  temperature 
of  160°  F.,  and  falling  to  120°  F.  at  the  close.  The  outline  of 
operations  here  given  is  one  of  modern  simplification,  somewhat 
as  conducted  by  planters  in  India,  and  considerably  less  elabo- 
rate than  the  methods  of  the  Chinese.  In  black  teas  the  greater 
extent  of  fermentation  and  the  sharper  "  firing  "  appear  to  re- 
duce the  quantity  of  tannin,  and  certainly  leave  the  tannin  and 
the  other  extractive  matters  in  a  less  readily  soluble  condition. 
Teas  contain  essential  oil,  which  is  undoubtedly  affected  by  the 
curing  process.* 

An  extended  investigation  of  teas  imported  into  the  United 
States  was  made  in  1884  by  Mr.  Geisler,  of  New  York,  who  is 


TEAS  OF  COMMERCE.  505 

engaged  in  the  analytical  chemistry  of  foods,  and  his  report  is 
of  great  scientific  and  practical  value.  The  tabular  summaries 
of  the  report,  and  Mr.  Geisler's1  principal  conclusions  bearing 
upon  the  methods  of  infusion  in  the  preparation  of  tea  as  a  bev- 
erage, are  presented  on  pages  506  to  508. 

In  Table  I.,  showing  the  principal  constituents  of  commer- 
cial teas,  it  will  be  noticed  that  there  is  no  uniform  relation 
existing  between  the  composition  of  teas  in  general  and  the  value 
of  the  same.  Teas  of  the  same  kind  from  the  same  district  would 
no  doubt  show  a  more  uniform  relation  as  to  composition  and 
price. 

The  percentage  of  extract,  determined  by  half-hour  boiling  of 
the  tea  leaf  in  one  hundred  parts  of  distilled  water,  bears,  at  least 
in  Oolong  and  Congou  teas,  a  more  uniform  relation  to  the  price 
than  the  other  constituents  determined,  although  the  total  ex- 
tract obtained  by  exhausting  the  leaf  is  very  irregular.  This  is 
quite  in  accord  with  a  fact  which  dealers  in  tea  are  aware  of — 
namely,  that  the  finer  and  more  valuable  qualities  of  tea  of  any 
line  consist  of  young  and  tender  leaves,  while  the  medium  and 
poorer  grades  contain  older  and  tougher  leaves.  The  younger  a 
leaf  is  the  more  tender  and  succulent  will  it  be,  and  it  therefore 
follows  that  it  gives  up  its  extractive  matter  more  readily  to 
water,  which  is  all  the  more  important  in  the  customary  house- 
hold method,  where  boiling  water  is  poured  upon  the  leaves  and 
allowed  to  draw  for  only  a  given  length  of  time. 

The  percentages  of  theine,  tannin,  and  soluble  ash  are  too  ir- 
regular to  show  any  relation  between  their  per  cents,  and  the 
price  of  the  tea.  It  appears  from  these  analyses,  however,  that 
the  finer  the  quality  of  the  tea  the  more  theine,  soluble  ash,  and 
extractive  matter  will  it  contain  ;  still,  the  same  is  not  uniformly 
true.  The  percentages  of  extract  (total)  and  insoluble  leaf  are 
still  more  irregular  when  compared  with  the  price  of  the  tea. 

The  results  in  Table  III.  are  of  greater  interest,  since  they 
show  the  principal  constituents  of  tea  which  are  actually  taken 
up  by  water  in  the  ordinary  preparation  of  tea  as  a  beverage. 

In  order  that  the  results  would  be  strictly  comparable,  the  in- 
fusions of  the  different  teas  were  all  prepared  under  precisely 

1  JOSEPH  F.  GEISLER,  Ph.C.,  chemist  to  the  New  York  Mercantile  Ex- 
change. 1884:  Am.  Grocer,  Oct.  23.  The  discussion  of  the  results  following 
(pp.  510,  511)  is  taken  wholly  from  Mr.  Geisler's  report.  "Although  the  che- 
mical composition  of  tea  has  frequently  been  made  the  subject  of  analytical 
inquiries  with  a  view  of  ascertaining  the  relation  existing  between  the  chemical 
composition  and  the  commercial  value  of  tea,  the  amount  of  work  previously 
done  relative  to  teas  of  this  market  is  very  meagre. " 


5o6 


TEAS  OF  COMMERCE. 


<nos 
-w%  uounuoa  poof) 


•noduoj  (nos 
-wjf  uouiuioo  poof) 


•noSuoQ 
Gmuojf   UOWWOQ 


•nofiuoQ 
uouiutoo 


"noSuoo 


timuojp 


•no&uoQ 


•noduoo 


9UM 


tiq 


t,aoo 
-*&} 


P9)X>C 


'  j,9panodun£) 
9un/iojf 


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-itnf)  9unfiojf  9U'itf 


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9unfioj\[ 


i 


S  e. 

TH  *> 


8    S 


g  M  s 


s    « 


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s  § 

oi     o 


g    S 

~  s 


%     S     ~     8 


3    9 

CO 


co     os      £      os 
ol      «?      2      ~ 


S      g 
j>     eo' 


8    S 

10      si 


»>          1-1 


SB    55 
d   S 


10      »-i      eo 


g      e§      3      S 

I-          OJ          10          T* 


I!    ! 


S    S 


10      1-1      co 


eo     co     10 
10      eo     T-I 

co'     eo     oi 


~        .     So 


t-      eo      O 

eo"     Tji      oi 


co      os 

$   d 


C       CO 


O        a-. 

§ 


eo      OJ      co 


S    S 


si 


*:  jf 


:    3 


I 

4)        •§         «)        <J 


i  s  I  i  = 
1 1  I  1  I 

t>l        H        5        H        5 


i     c 

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W  ^i     ^ 

if! 

11! 

*     o 


G  wju 

s  p-5 


1^2. 


i      >Q     gj  *— '  frj     ^ 

«-3ST5S 

G      -  S    **   d,^ 

£  c  C^TJ  aj'g 

sg^SSS 

«5!1« 

111 


TEAS   OF  COMMERCE. 

2  2    \  °*  ® 


507 


fioiuy  uimpvjv 


•6uojoo  vsouuog  i39wi£ 


•&UOIOQ  fi<nu>v  uowiuoo 


•6wpo  Aouty 


ftowy 


•DUOJOQ 


os&uuog 


poof) 


•SUOJOQ  VSOUUOjf  MU9(InS 


fe 


5    S         S 


S    S 

(»     eg 


S    S 

in     ci 


0  o       jo 


S 


JS    fe    §8 


00     °' 


^  ^     S 


•Gwioo 


•6UOJOQ 


DSOUUOtf 


«    S 

^      in 


o      «o      t> 


s       GO      10      IN      eo 


O  »0       T-. 


9  '»«>j;  umpuj 


•Q  '»9j;  uvipui 


'V9J,  umpui 


'V9tl  UWtpltf 


'Z  "09J, 


'I  'V9J, 


oo     o      0 


I  s'-i 


. 

3  i  ?t  1 
* 


:    .S 


S  .S  " 


e  e  6  1  ?  ft1* 


508 


TEAS   OF  COMMERCE. 


1 

•898HfOUy  /0  'OJf 

CO 

CD 

a 

"PPY  -josuf  ysy 

MM     MM 

CO       CO  §N       CO 

»*       s 

•yay  9jqn2osuf 

OtCOCS^                    IVT^CO1^ 

N     S     ^     A             SSSS 
oi     TH     oi     ui            eo     t-J     oi     ei 

SB    S    S    g 

•y#y  9jqniog 

co     eo     eo     eo'             co*     oi     co     eo' 

S    S    8    88 

eo'     oi     co     eo' 

•ysy  fDjojj 

S2  2  2     3  3  S  2 

CO       )Q       1Q       CO 

,_j 

•*** 

cooot-oS             Si2co^* 

So     e     e5     S 
oi     r-i     w     ci 

P 

S 

•umunj, 

06     eo"     n<      »o             o     T-J     co     i> 

8    ^    S    S 

CO       OO       T—  t       C$ 

PQ 

2 

>— 

oS^eo             i2ooooS 

SOD       TH       •<*                  CO       ^       O       CO 
•*       O       »O                  »O       ••*       1O       ift 

§^*     t»     oi 
»o     fo     co 

•gOVAlXg  IVfOJj 

1  "  i  1   i  i  s  i 

800       JO       QQ 
^r      CO      "^r 

•     fe  JT  8  fe 

'3ovj,)x$f  '•'//  i/^/7 

COOt^CO                  G^OQO(^ 

8    i    8S    1 

'9J,niswf[ 

8    35    5S      :         §B    S    8      . 

JS    cS    S5      . 

e»     t>     06 

1 

•'        : 

11 

o                      .     : 

: 

Averages  calculated  upon  t) 
lea,  unless  otherwise  st 

5              *•  S              ?: 

B          1   §           § 

s          1  «          s 

'  1      g        1 
j|||     |  {  i  1 
III!     1141 

CONGOUS. 
Maximum  .  .  . 

Minimum  
Average  dried  at  100°  C  

TEAS  OF  COMMERCE. 


509 


-OJY  uouiutoo 


aioswx 
uoutuioo  poof) 


2       8 


CO  J8 

oo          « 


8          - 


•noGttoo  6mu 


•noBuoj  6mu 


Homy  WMpffl 


8 ~ 


•Suojoo 


J_A 


•BUOJOQ  mow 


'Suojoo  mom 


8       g 

co          eo" 


s     - 


•Suojoo  mom 


-uvj 


g     3 
g     s 


io         ei 

g     d 


os          ^ 


-(nodvnf)  mn 


•^period 


-unf) 


S       g 


3       3 


•V9J,  UWtpllf 


•»9jj  umpuj 


S        rt 


S3 
•Sis 

x~,  S  '^ 

4-5.S  S3 

gss 


i  a  a 

«  I§  !§. 

,d  -fia    «fl^  Qo-a 

S         O>— "          "^      .  ..  TH   O> 

I  =1  II!  a|! 

0  (3  ^  O    -  " 


tannin, 
100  pa 


E   £ 


M  ^    i-i     «. 

1  &"§& 


dra 
t 


eg 


Ratio  (per  cent.)  tai 
10  minutes  in  100  p 
total  tannin  in  lea 


1 5 

"3  «j 

§t 
1! 


Per  c 
draw 
wate 


5io       .  TEAS  OF  COMMERCE. 

the  same  conditions.  The  results  cannot  be  considered  absolute, 
but,  as  they  vary  only  between  narrow  limits,  they  are  sufficiently 
accurate  to  illustrate  the  behavior  of  these  various  teas  when 
subjected  to  the  customary  household  method  of  pouring  boiling 
water  upon  the  leaves  and  allowing  it  to  draw. 

The  results  of  this  table  (III.)  give  the  percentages  of  "  ex- 
tract," theine,  tannin,1  ash  (mineral  matter)  dissolved,  the  alka- 
linity of  the  ash  expressed  as  potassium  oxide,  and  the  ratio  (per 
cent.)  of  "extract"  and  tannin  to  the  total  amount  of  these  two 
in  the  leaf.  The  percentages  are  calculated  upon  the  air-dried 
leaf.  A  comparison  of  the  results  for  the  five  Oolong  teas  shows 
the  finer  grades  to  have  yielded  more  extract,  theine,  and  ash 
than  the  poorer  grades. 

The  decline,  from  the  fine  to  the  poor  grades  of  the  various 
teas,  in  the  amount  of  theine  dissolved,  is  something  noteworthy, 
as  showing  the  fine  grades  to  yield  nearly  all  their  theine,  while 
the  poorer  grades  do  so  only  to  a  limited  extent.  The  percent- 
ages of  tannin  are  quite  irregular.  Further,  the  table  shows  that 
there  is  more  mineral  matter  extracted  from  the  leaf  than  is 
indicated  by  the  term  "  soluble  ash  "  in  Table  I.,  the  difference 
being  .62  per  cent,  as  an  average  of  fourteen  determinations. 

The  ratio  of  tannin  to  the  "extract,"  and  the  ratio  of  either 
one  to  the  total  tannin  and  "  extract "  of  the  leaf,  varies  quite 
uniformly  with  the  value  of  the  tea,  the  per  cent,  of  tannin  fall- 
ing or  rising  with  the  percentage  of  u  extract."  See  Table  IV. 

It  will  also  be  noticed  that  the  Congou  teas  yielded  low  per- 
centages of  "  extract "  and  tannin,  showing  that  the  time  allowed 
for  drawing  in  these  teas  should  be  greater  than  ten  minutes,  if 
a  full  yield  of  these  constituents  is  desired.  If  this  is  uniformly 
true  of  Congou  teas,  they  would  certainly  be  suitable  for  people 
to  whom  the  large  quantity  of  tannin  of  the  other  varieties  is 
objectionable.  The  tannin  extracted  from  the  best  green  tea  was 
unusually  large,  being  16.79  per  cent. 

Both  Indian  teas  show  a  good  yield  of  "  extract,"  theine,  tan- 
nin, and  soluble  mineral  matter.  Although  these  results  are 
quite  satisfactory  in  showing  the  difference  in  the  drawing  quali- 
ties of  various-priced  teas,  they  are  not  sufficiently  uniform  to 
make  the  results  of  an  analysis  the  basis  for  calculating  the  price 
of  a  tea.  It  is  evident  that  the  essential  oil  plays  a  more  impor- 
tant part  than  any  other  constituent  of  the  tea  in  determining  its 
commercial  value. 

'The  percentages  of  tannin  are  somewhat  greater  than  would  be  obtained 
in  using  a  hard  water. 


TEAS   OF  COMMERCE. 
TABLE  IV. 


FINEST  FORMOSA  OOLONG. 

theine,  and  ash  dissolved  from  tea  by  dis- 
tilled water  and  Croton  water,  by  allow- 

1 

1 

| 

1 

| 

1 

ing  to  draw  from  three  minutes  to  over 

•S  5* 

Is  b 

o 

"og 

g 

one  hour.    (One  hundred  parts  of  boiling 
water  were  poured  upon  one  part  of  tea.) 

1 

SI 

55 

. 

|1 

g£ 

g 

g 

g 

V« 

• 

TO 

us 

0 

0 

0 

~ 

Per  cent  extract  total 

25  97 

28  37 

27  47 

30  87 

30  25 

oq  r-c 

Per  cent  extract  less  ash 

22  25 

24  50 

23  85 

26  70 

26  ">2 

29  42 

Per  cent,  tannin     

9  755 

11  23 

10  18 

13  46 

10  60 

14  94 

Per  cent,  theine  

1  95 

2  65 

2  02 

2  75 

2  82 

2  85 

Alkalinity  of  ash  as  potassic  oxide  

1  029 

1  22 

1  076 

1  22 

1  152 

1  28 

Per  cent  ash 

3.725 

3.805 

3.625 

4.175 

4.125 

4.325 

Table  1Y.  illustrates  the  difference  in  the  drawing  quality  of 
an  extra  choice  Oolong  tea  when  treated  either  with'distilled  or 
Croton  water.  It  shows  that  in  ten  minutes'  "  drawing  "  the 
theine  was  practically  extracted,  and  that  the  Croton  water  ex- 
tracted less  tannin  than  the  distilled  water,  while  there  was  no 
noteworthy  difference  in  the  percentages  of  extract  and  ash 
when  the  distilled  water  and  Croton  water  were  allowed  to  draw 
for  the  same  length  of  time.  Hard  waters  dissolve  less  tannin 
than  soft  waters  under  the  same  conditions.  This  will  also  be 
noticed  in  the  above  table.  And  Table  IY.  serves  to  illustrate 
the  rapidity  with  which  the  constituents  of  the  tea  leaf  are  dissolv- 
ed, and  that  the  choice  of  the  water  and  the  proper  length  of 
time  for  drawing  are  very  important  factors  in  preparing  a 
good  cup  of  tea. 

Practical  conclusions. — Though  varying  widely  for  different 
teas,  the  total  soluble  (extractive)  matter  averages  about  33  per 
cent.,  but  the  average  is  considerably  lower  for  the  infusion  of 
tea  prepared  by  the  ordinary  household  method.  The  volatile  oil 
gives  the  flavor  and  aroma,  the  tannin  and  extractive  matter  the 
astringency,  strength,  and  body  to  the  infusion.  Theine,  being 
almost  tasteless,  is  not  taken  into  account  by  "  tea-tasters," 
though,  physiologically,  the  most  important  constituent  of  the 
tea. 

Besides  the  above,  the  appearance  of  the  leaf,  as  well  as  the 
color  of  the  infusion  and  any  peculiar  foreign  taste  or  smell 
imparted  to  the  same,  have  considerable  bearing  in  the  "  tea- 


512  /  THEOBROMINE. 

taster's  "  method  of  valuation.  A  strict  relation  between  tlie 
chemical  composition  of  the  tea  and  the  commercial  value  of 
the  same  is  therefore  scarcely  to  be  looked  for,  although  the 
former  would  disclose  at  once  that  tea  which  is  physiologically 
the  best. 

The  principal  constituents  of  tea  are  the  volatile  oil,  theine, 
tannin,  albuminous  compounds,  gum,  etc.,  and  the  soluble 
mineral  matter,  containing  considerable  potash  and  phosphoric 
acid. 

The  fertility  of  the  soil,  the  nature  of  the  climate,  the  pro- 
cessing and  manipulation  the  leaves  undergo  after  being  pluck- 
ed, and  the  care  with  which  the  tea  is  handled  thereafter  are  all 
instrumental  in  influencing  the  chemical  composition  and  the 
quality  of  the  tea.  Uniformity  in  composition  cannot  be  ex- 
pected. The  principal  difference  between  Green,  Oolong,  and 
Congou  teas  is  caused  by  the  processing  and  manipulation  ;  but, 
whatever  the  modus  operandi  of  the  latter,  it  cannot  make  good 
tea  out  of  leaves  which  have  not  had  the  proper  conditions  of 
soil  and  climate  to  further  the  production  of  those  constituents 
which  are  characteristic  of  tea.  In  the  ordinary  analysis  of  the 
tea  only  the  more  important  constituents  are  determined,  in 
order  to  establish  the  presence  or  absence  of  foreign  matter. 
The  results  thus  obtained  are  scarcely  applicable  to  the  commer- 
cial valuation  of  tea,  since  much  is  there  determined  which  does 
not  enter  the  infusion  of  tea.  It  is  the  quality  of  the  infusion 
which  is  of  importance  to  the  consumer,  and  not  the  total  com- 
position or  appearance  of  the  leaf.  Tea  is  essentially  something 
for  the  epicurean.  To  discriminate  between  qualities  of  teas  of 
nearly  the  same  grade  requires  a  delicate  and  sensitive  palate. 
Expert  tea-tasters  are  guided  chiefly  by  the  strength,  flavor, 
aroma,  and  quality  of  the  infusion  in  judging  and  classifying  tea 
as  to  its  quality. 

THALLINE.     See  CINCHONA  ALKALOIDS,  p.  168. 
THEBAINE.     See  OPIUM  ALKALOIDS,  p.  358. 
THEINE.     See  CAFFEINE,  p.  77. 

THEOSROMINE.-C7H8N402  =  180.  A  dimethyl  xan- 
thine,  C5H2(CH3)2N4O2 .  See  Caffeine,  p.  77. — Found,  without 
caffeine,1  in  the  seed  of  the  Theobroma  Cacao,  or  "  chocolate 

1  SCHMIDT  (1883)  found  a  little  caffeine  in  cacao. 


THEOBROMINE.  513 

nut "  (WOSKRESENSKY,  1841),  and,  as  a  smaller  accompaniment 
of  caffeine,  in  the  seed  of  the  Sterculia  acuminata,  the  "  cola 
nut."  The  dry  cacao  seed  freed  from  husk,  the  "  cocoa  nibs," 
contains  about  1.5  percent,  of  theobromine  (WOLFRAM,  1879) ; 
while  the  husks,  the  ''  cocoa  shells,"  furnish  from  0.3  to  0.7  per 
cent,  in  average  yield  (WOLFRAM,  DONKER,  1880). 

a. — Theobromine  crystallizes  in  the  trimetric  system,  appear- 
ing in  permanent,  anhydrous  white  needles  and  club-shaped 
groups,  to  the  unaided  eye  as  a  crystalline  powder.  Sublimes 
without  decomposition,  yielding  distinct  microscopic  crystals 
of  sublimate  at  170°  C.  (BLYTH,  1878).  Sublimes  at  290°  to 
295°  C.  (KELLER,  1854). 

b. — Theobromine  has  a  very  bitter  taste,  slowly  produced. 
Its  physiological  effects  are  like  those  of  caffeine,  but  are  ob- 
tained by  smaller  doses  (MITSCHERLICH,  1859).  It  is  excreted  in 
the  urine. 

c. — Theobromine  is  slightly  soluble  in  water  or  alcohol,  its 
solution  requiring  1600  parts  water  at  17°  C.  (62.6°  F.),  and  148 
parts  water  at  100°  C.  (DRAGENDORFF)  ;  4284  parts  absolute  alco- 
hol at  17°  C.,  and  422  parts  boiling  absolute  alcohol  (TREUMANN, 
1878),  in  1400  parts  cold  alcohol  (MITSCHERLICH,  1 859).  It  is 
but  very  slightly  soluble  in  ether,  one  part  requiring  17000  parts 
cold  ether  or  600  parts  boiling  ether  (Mitscherlich).  It  dissolves 
in  105  parts  boiling  chloroform  (Treumann) ;  is  somewhat  solu- 
ble in  amyl  alcohol ;  but  slightly  soluble  in  benzene ;  insoluble 
in  petroleum  benzin. — Theobromine  is  a  weak  base.  It  forms 
crystallizable  salts  ;  but  on  contact  with  water  they  give  up  acid 
and  become  basic  salts,  and  those  of  volatile  acids  give  up  the 
acid  at  or  below  100°  C.  Theobromine  dissolves  in  hydrochloric 
and  in  other  acids  ;  but  the  hydrochloride,  C7H8N4O2 .  HC1 .  H2O, 
and  the  nitrate,  C7H8N4O2.HNO3,  do  not  dissolve  at  all  freely 
in  water  alone  without  free  acid.  Theobromine  dissolves  in 
ammonia-water.  Respecting  combinations,  see  report  of  Messrs. 
SCHMIDT  and  PRESSLER,  1883. ' 

d. — Theobromine  responds  to  the  murexoin  test  with  the 
same  intensity  as  Caffeine  (p.  79),  forming  amalic  acid  when 
warmed  with  hydrochloric  acid  and  potassium  chlorate  and 
evaporated  to  dryness  on  the  water-bath,  and  giving  purple- 
colored  murexoin  when  the  cold  residue  is  touched  with  am- 
monia.— Phosphomolybdate  of  sodium,  added  to  the  acidulous 

1  Liebig's  Annalen,  217,  287;  Jour.  Chem.  Soc.,  44,  872. 


TYRO  TO  XI  CON. 

solutions  of  theobrornine,  gives  a  yellow  precipitate,  obtained 
in  dilute  solutions.  —  Platinum  chloride  does  not  precipitate, 
except  in  concentrated  solutions,  when  crystals  are  obtained, 
(C7H8N4O2)2H01PtCle.4H2O.  In  like  manner  gold  chloride 
yields  yellow  crystals,  in  tufts  of  needles,  C7H8N4O2  .  HC1  .  Au013. 

—  When  an  ammonia  solution  of  theobromine  is  treated  with 
silver  nitrate  solution,  a  gelatinous  precipitate  is  obtained,  and 
on  boiling  this  granular  crystals  of  argentic  theobromine  are  ob- 
tained, C7H7AgN4O2.  And  when  this  compound  is  treated 
with  anhydrous  methyl  iodide,  at  100°  C.,  for  twenty-four 
hours,  caffeine  (methyl  theobromine)  is  formed,  with  silver 
iodide  (STRECKER,  1861).  Again,  when  theobromine,  alcoholic 
solution  of  potassium  hydrate,  and  methyl  iodide,  in  equiva- 
lent quantities,  are  heated  together  at  100°  C.  in  sealed  tubes, 
caffeine  is  formed,  with  potassium  iodide  (SCHMIDT  and  PRESSLER, 
1883). 

C7H7Ag]Sr402  +  CH3I  =  C7H7(CH3)ISr402  +  Agl 

C7H8N4O2  +  CH3I  +  KOH  =  C7H7(CH3)N4O2  +  KI  +  H2O. 

Potassium  mercuric  iodide  produces  no  precipitate  in  the  acidu- 
lous solutions  of  theobromine,  and  iodine  in  potassium  iodide 
solution  causes  little  precipitation  (distinctions  of  caffeine  and 
theobromine  from  most  other  alkaloids). 

e.  —  Theobromine  may  be  separated  from  non-volatile  mat- 
ters, in  general,  by  sublimation  at  a  gradually  increasing  heat 
beginning  at  170°  C.  From  most  alkaloids  by  its  slight  solubi- 
lities, and  from  caffeine  by  its  smaller  solubilities  in  benzene 
(SCHMIDT),  or  water,  or  ether. 


>  —The  quantitative  estimation  of  theobromine  in  cacao  is 
made  by  SCHMIDT  and  PRESSLER  (1883)  as  follows  :  The  crushed 
cacao  is  freed  from  oil  by  pressure,  half  its  remaining  weight 
of  slaked  lime  is  added,  and  the  mixture  is  boiled  repeatedly 
with  alcohol  of  80  per  cent,  strength.  The  residue  on  evapora- 
tion of  the  alcohol  is  recrystallized  from  the  same  solvent,  and 
is  obtained  as  a  white,  crystalline  powder.  It  may  be  dried  at 
100°  C.  and  weighed. 

TROPEINES.     See  MIDRIATIC  ALKALOIDS,  p.  339. 
TURKEY-RED  OIL.     See  FATS  AND  OILS,  p.  287. 

TYROTOXICON.—  "  Cheese  Poison."     The  putrefactive 
product  obtained  in  1885  by  Professor  Yaughan,  and  recently 


TYROTOX1CON.  515 

announced  by  him  to  be  diazoberizene,  C6!I5.N:N,  in  combina- 
tion with  acids.1 

a. — Tyrotoxicon,  obtained  from  milk  products  as  direct- 
ed under  e,  was  found  to  agree  with  diazobenzene  butyrate, 
C6H5 .  E~2 .  C4H7O2 ,  in  crystallizing  in  needles,  which  gradually 
decompose  in  moist  air.  Potassium  diazobenzene,  C6H5.  N2.  OK, 
obtained  from  tyrotoxicon,2  appeared  in  line  six  sided  plates. 
Tyrotoxicon  compounds,  at  100°  C.,  explode  with  violence. 

b.  The  crystals  have  a  penetrating,  old-cheesy  odor.  A 
minute  portion  placed  upon  the  tongue  produces  "  dryness  of  the 
throat,  nausea,  vomiting,  and  diarrhoea."  In  children  the  effects 
agree  with  the  symptoms  of  cholera  infantum.  Ten  drops  of  a 
concentrated  aqueous  solution  of  tyrotoxicon  from  milk  three 
months  old,  placed  in  the  mouth  of  a  small  dog  three  weeks  old, 
in  a  few  minutes  caused  "  frothing  at  the  mouth,  retching, 
vomiting  of  frothy  liquid,  rapid  breathing,  muscular  spasm  over 
the  abdomen,  and  after  some  time  watery  stools."  Similar  ef- 
fects were  obtained  with  cats,  and  subsequent  dissection  showed 
the  mucous  membrane  of  the  stomach  and  intestines  to  be 
blanched  and  soft.  Of  diazobenzene  butyrate,  artificially  pre- 
pared,3 0.010  to  0.025  gram  given  to  cats  caused  severe  symptoms, 
the  same  as  above  detailed,  and  0.100 gram  caused  death,  the  mu- 
cous membrane  of  the  stomach  not  being  reddened,  but  left  pale 
and  soft. 

G. — "  Tyrotoxicon  is  soluble  in  water,  alcohol,  chloroform, 
and  ether."  "  Purified  tyrotoxicon  is  insoluble  in  ether,  and  it 
probably  owes  its  solubility  in  ether  at  this  stage  to  the  presence 
of  impurities."  The  ordinary  salts  of  diazobenzene  are  more  or 
less  freely  soluble  in  water,  sparingly  soluble  in  alcohol,  and  are 
for  the  most  part  precipitated  from  alcoholic  solutions  by  ether. 

d. — The  diazobenzenoid  compounds  are  identified  by  the 
reaction  of  LIEBEKMANN,*  namely,  by  the  bright  colors  they  give 

'VICTOR  C.  VAUGHAN,  1884-85:  "A  Ptomaine  from  Poisonous  Cheese," 
Zeitsch.  phyxiolog.  Chem.,  10,  146;  Jour.  Chem.  Soc.,  50,  373.  Michigan  State 
Board  oi'  Health  Reports,  1885  and  after.  "Tyrotoxicon:  Its  presence  in  poi- 
sonous cheese,  ice-cream,  and  milk,"  Am.  Assoc.  Adv.  Sci.,  Buffalo  Meeting, 
August,  1886,  Jou/:  A'nalyt.  Chem.,  i,  24.  "The  Chemistry  of  Tyrotoxicou 
and  its  action  upon  the  lower  animals,"  with  report  of  determination  of  diazo- 
benzeno,  ibid.,  i,  281. 

*  By  method  of  GRIESS,  1866:  Ann.  Chem.  Phar.,  137,  54. 

3  By  the  method  of  (JRIKSS,  loc.  cit. 

4LiEBERMANN,  1874:  Bar.  d.  chem.  Ges.t  7,247;  Jour  Chem.  Soc.,  27. 
693:  that  sulphuric  acid  holding  nitrous  acid  in  solution  gives  color-reactions 


5 1 6  TYRO  TOXICON. 

when  treated  with  concentrated  sulphuric  acid  and  phenol. 
"  "With  equal  parts  of  sulphuric  acid  and  carbolic  acid  the  pre- 
pared [artificial]  diazobenzene  nitrate  gave  a  green  coloration ; 
while  with  the  same  reagents  tyrotoxicon  gave  a  color  which 
varied  from  a  yellow  to  an  orange-red.  But  the  diazobenzene 
nitrate  dissolved  in  the  whey  of  normal  milk  and  extracted  with 
ether,  or  in  the  presence  of  other  proteids,  gave  the  same  shades 
of  color  as  the  tyrotoxicon  did,  and  the  potassium  compound  of 
tyrotoxicon  prepared  by  the  method  to  be  given  later  produced 
the  same  shade  of  green  as  did  the  artificial  diazobenzene.  This 
color  test  may  be  used  as  a  preliminary  test  in  examining  milk 
for  tyrotoxicon.  It  is  best  carried  out  as  follows :  Place  on  a 
clean  porcelain  surface  two  or  three  drops  each  of  pure  sulphuric 
acid  and  pure  carbolic  acid.  This  mixture  should  remain  color- 
less, or  nearly  so.  Then  add  a  few  drops  of  the  residue  left  after 
the  spontaneous  evaporation  of  the  ether.  If  tyrotoxicon  be 
present  a  yellow  to  an  orange-red  color  will  be  produced.  This 
test  is  to  be  regarded  as  a  preliminary  one ;  for  it  may  be  due  to 
the  presence  of  a  nitrate  or  nitrite.1  The  tyrotoxicon  must  be 
purified  according  to  a  method  to  be  given  further  on  before  the 
absence  of  nitrate  or  nitrite  can  be  positively  demonstrated." 

The  explosion  of  tyrotoxicon  may  be  obtained,  in  evidence 
of  its  identity,  by  exposure  of  the  platinochloride  to  a  tempera- 
ture approaching  100°  C.,  as  in  the  discovery  of  this  property  by 
Prof.  Yaughan.  A  solution  of  the  tyrotoxicon  in  absolute  alco- 
hol is  treated  with  a  little  platinum  chloride,  and  heated  in  an 
open  dish  upon  the  water- bath,  when,  as  the  alcohol  is  nearly  or 
quite  all  vaporized,  the  explosion  results.  The  known  diazo  pla- 
tinum compound  is  (C6H5 .  N2 .  Cl)2PtCl4 ,  and  in  explosion  is 
resolved  into  2C6H5C1  +  N2  +  2C12  +  Pt. 

The  aurochloride  of  tyrotoxicon  is  obtained,  in  precipitate  or 
in  golden  plates,  as  follows  :  "  In  the  nitrate  from  milk  which  is 
rich  in  tyrotoxicon,  after  neutralization  with  sodium  carbonate, 

with  phenols  generally,  the  produced  colors  containing  nitrogen  but  not  in  the 
form  of  the  nitro,  and  probably  not  in  that  of  the  nitroso  group. 

All 'diazo  compounds,  also  the  diazo-amido  compounds,  share  with  the  ni- 
troso compounds  (Hofmann)  and  the  nitrites  (Liebermann)  the  power  to  give 
with  sulphuric  acid  and  phenol  red  to  blue  colors  of  the  utmost  intensity  (E. 
FISCHER,  1875).— The  color-products  so  obtained  are  azo-benzenoid bodies,  well 
known  as  azo  dyes,  represented  by  the  tropceolines  (this  work,  p.  186;  O.  N. 
WITT,  Jour.  Ghem.  Soc.,  35,  179).  The  azo  compounds,  it  will  be  remembered, 
contain  the  group  NN  interposed  between  two  benzenoid  (or  other  carbona- 
ceous) groups.  Thus,  C6H4.N2 .  S03  (diazobenzene  sulphonic  acid)+06H5OH  = 
CeH-t.SOaH.Na.CeBU.OH  (oxy-azo-benzene  sulphonic  acid). 

1  "  The  coloration  with  nitrates  and  nitrites  is  darker  than  with  diazoben- 


TYROTOXICON.  517 

filtration  and  acidifying  with  hydrochloric  acid,  gold  chloride 
produces  a  precipitate  which  is  insoluble  in  water,  but  soluble  in 
Aot  alcohol,  from  which  it  separates,  on  cooling,  in  golden  plates." 
"  The  gold  compound  is  decomposed  by  frequent  treatment  with 
hot  alcohol." 

The  potassium  compound  of  tyrotoxicon  —  believed  to  be  po- 
tassium diazobenzene,  C6H5.N2.OK  —  was  prepared  as  follows: 
"  The  aqueous  residue  [see  e]  was  acidified  with  nitric  acid,  then 
treated  with  an  equal  volume  of  potassium  hydrate  and  the 
whole  concentrated  on  the  water-bath.  .  .  .  On  cooling  the  mass 
crystallized  ...  in  six-sided  plates,  along  with  the  prisms  of  po- 
tassium nitrate.  The  crystalline  mass  obtained  from  the  tyro- 
toxicon was  treated  with  absolute  alcohol,  filtered,  the  filtrate 
evaporated  on  the  water-bath,  the  residue  dissolved  in  absolute 
alcohol,  from  which  it  was  precipitated  in  a  white,  crystalline 
form  with  ether." 

The  decompositions  of  tyrotoxicon  are  so  far  found  by  its 
discoverer  to  agree  with  the  well-known  decompositions  of  diazo- 
benzene salts.  Warmed  with  water  the  latter  break  up  into  car- 
bolic acid  and  nitrogen,  thus  : 


C6H5  .  N2  .  M)3  +  H20  =  C6H5  .  OH  +  ]ST2 
Warmed  with  alcohol,  aldehyde  and  hydrocarbons  result  as  fol- 
lows : 


C6H5  .  N2  .  K03  +  C2H60  =  C6H6  +  N2  +  C2H40 

With  the  acids  of  the  halogens  changes  occur  as  follows  : 

C6H5  .  1ST  2  .  ]ST03  +  HC1  =  C6H5C1  +  N2  +  HNO3  . 

The  reducing  agents  in  general  cause  immediate  decomposition. 
Hydrogen  sulphide  reacts  promptly. 

e.  —  The  following  directions  for  the  separation  of  tyrotoxicon 
from  milk  or  cheese  are  taken  from  the  last  article  of  Dr. 
Vaughan  :  "  Milk  or  other  fluid  to  be  tested  for  this  poison 
should  be  kept  in  well-stoppered  bottles  ;  for  if  the  fluid  be  ex- 
posed to  the  air  the  tyrotoxicon  may  decompose  in  a  few 
hours.  The  filtrate  from  the  milk,  or  the  filtered  aqueous  ex- 
tract of  cheese,  should  be  neutralized  with  sodium  carbonate, 
then  shaken  with  half  its  volume  of  pure  ether.  Time  should 
be  given  for  the  complete  separation  of  the  ether.  .  .  .  After 
complete  separation  the  ether  should  be  removed  with  a  pipette 
and  allowed  to  evaporate  spontaneously  in  an  open  dish.  The 
residue  from  the  ether  may  be  dissolved  in  distilled  water  and 
again  extracted  with  ether  ;  but  repeated  extractions  with  ether 
are  to  be  avoided,  for  as  the  tyrotoxicon  becomes  purified  it  be- 


5i8  VALERIC  ACIDS. 

comes  less  soluble  in  ether.  To  a  drop  of  an  aqueous  solution 
of  the  ether  residue  apply  the  preliminary  test  with  sulphuric 
and  carbolic  acids.  To  the  remainder  of  the  aqueous  solution 
of  the  ether  residue  add  an  equal  volume  of  a  saturated  solution 
of  caustic  potash,  and  evaporate  the  mixture  on  the  water-bath. 
The  double  hydrate  of  potassium  and  diazobenzene[C6H5.N2.OK] 
will  be  formed  if  tyrotoxicon  be  present."  The  recognition  of 
potassium  diazobenzene  is  stated  on  page  517. 

f. — An  estimation  of  tyrotoxicon  is  indicated  by  the  experi- 
ments of  Vaughan,  in  converting  the  potassium  compound  (d), 
prepared  as  directed  (#),  into  potassium  sulphate  for  weight. 
The  white,  crystalline  precipitate,  by  the  ether,  "  was  collected, 
washed  with  ether,  dried,  and  the  per  cent,  of  potassium  esti- 
mated as  potassium  sulphate.'' 1 

K2S04  :  2C6H5N2OK  :  2C6H5N2lSrO3::174  :  320  :  334. 

ULTIMATE  ANALYSIS  OF  CARBON  COMPOUNDS  See 
p.  201. 

VALERIC  ACIDS.  C5H19O2  ==  102  (monobasic):  Pri- 
mary Pentoic  Acids. — Four  pentoic  acids  are  theoretically  pos- 
sible, as  oxidation  products  of  the  four  primary  pentoic  alcohols, 
and  are  all  known,  as  follows  : 

(1)  Normal  valeric   acid,    CI13.CII2.CH2.CH2.CO2H.      Made 

from  normal  butyl  cyanide,  etc. 

(2)  Isovaleric  acid.      Inactive   valeric  acid.       (CH3)2CH.CH2. 

CO2H.  Isobutyl-carboxyl.  Chief  valeric  acid  of  vale- 
rian oil.  Obtained  by  oxidation  of  the  chief  alcohol  of 
fusel  oil. 

(3)  Methyl-ethyl  acetic  acid.       Active   (dextro-rotatory)    valeric 

acid.  CH3.C2H5.CH.CO2H.  In  small  proportion  in 
valerian  oil,  according  to  some  observers.  Obtained  by 
oxidation  of  the  lesser  pentyl  alcohol  (13$)  of  fusel  oil. 

(4)  Methyl-prcpyl  acetic  acid,  CII3C3H6.CO2H.      Made   from 

methy  1-propy  1-  carbin  ol . 

ORDINARY  VALERIC  ACID.  ISOVALERIC  ACID  Inactive 
Valeric  Acid.  The  second  of  the  pentoic  acids  above  named. 
Baldriansaure. — A  constituent  of  u  valerian  root,"  the  rhizome 
and  rootlets  of  Valeriana  officinalis,  and  a  part  of  the  volatile  oil 
of  valerian.  Reported  as  found  in  digitalis,  Artirnisia  Absin- 

1  Per  cent,  of  potassium  calculated,  24.42;  found,  23.92. 


ORDINA RY  VA LERIC  A CID.  5 1 9 

thium,  Anthemis  nobilis,  Sambucus  nigra,  Yiburnum  opulus, 
and  other  plants.  Manufactured  by  oxidation  (distillation  from 
dichromate  and  sulphuric  acid)  of  isoamyl  alcohol  (isobutyl  car- 
binol),  the  principal  alcohol  of  fusel  oil. 

Valeric  acid  is  recognized  by  its  odor  and  the  odor  of  amyl 
valerate  (&),  its  solubilities  (<?,  d\  and  physical  properties  (a). 
It  is  separated  by  distillation  or  by  shaking  out  with  ether  (e). 
It  may  be  estimated  volumetrically  (/").  Tests  of  purity  (g). 

a. — Isovaleric  acid,  absolute,  is  a  colorless  oil,  of  specific 
gravity  0.93T  at  15°  C. ;  0.931  to  0.933  at  20°  C.  (water  at  same) 
(LANDOLT,  1862).  It  boils  at  175°  C.  (FRANKLAND  and  DUPPA, 
1867).  It  forms  a  hydrate,  C5H10O2.H2O,  of  sp.  gr.  0.950,  boil- 
ing  at  165°  C.,  and  gradually  dehydrated  by  distillation. 

The  metallic  valerates  are  easily  fusible  salts,  congealing  with 
an  opaque  white  surface,  and  crystallizing  by  careful  concentra- 
tion of  solutions. 

&. — Isovaleric  acid  has  an  acidulous,  burning  taste,  and  a  bit- 
ing effect  on  the  tongue.  The  odor  is  characteristic,  unpleasant, 
reminding  of  rancid  cheese.  The  metallic  valerates  are  nearly 
odorless,  and  of  a  sweetish,  sharp  taste.  Ethyl  and  amyl  vale- 
rates  have  fragrant,  heavy  fruity  odors.  Amyl  valerate  is  used 
to  present  an  odor  of  apples. 

c. — Isovaleric  acid  is  soluble  in  about  30  parts  of  water  at 
ordinary  temperatures,  the  hydrate  somewhat  more  soluble.  By 
saturation  of  the  solution  with  calcium  or  sodium  chloride  the 
valeric  acid  is  almost  wholly  thrown  out  of  solution.  It  is  solu- 
ble in  all  proportions  of  alcohol,  ether,  chloroform,  or  glacial 
acetic  acid, 

The  valerates  of  the  alkali  metals  are  deliquescent  and  freely 
soluble  in  water  and  in  alcohol;  of  the  alkaline-earth  metals, 
moderately  soluble  in  water  and  in  aqueous  alcohol.  Aluminium 
valerate  is  not  soluble  in  water;  basic  ferric  valerate,  insolu- 
ble ;  zinc  valerate,  in  90  parts  of  water  or  60  parts  of  80$  alco- 
hol ;  bismuth  valerate  (basic),  insoluble  in  water ;  lead  valerate, 
(normal)  soluble  in  water,  (basic)  sparingly  soluble ;  mercuric 
valerate,  soluble ;  mercurous  valerate,  slightly  soluble ;  cupric 
valerate,  moderately  soluble ;  silver  valerate,  slightly  soluble,  in 
water. — To  test-papers  free  valeric  acid  has  the  acid  reaction ; 
the  alkali  valerates,  neutral  reaction. 

d. — Isovaleric  acid  is  characterized  by  its  odor  as  a  free  acid, 
and  by  the  odor  of  its  amyl  ester.  This  is  formed  by  distilling 
with  a  little  ordinary  amyl  alcohol  and  twice  its  quantity  of 


520  VALERIC  ACIDS. 

sulphuric  acid.  Precipitates  are  obtained,  with  alkali  valerates. 
on  adding  aluminium  sulphate  or  silver  nitrate,  not  by  addition 
of  lead  normal  acetate.  Gupric  acetate,  with  concentrated  free 
valeric  acid,  yields  oily  droplets  of  anhydrous  valerate  of  cop- 
per, which,  on  standing,  crystallize  as  hydrate  (distinction  from 
butyrate,  which  in  solution  not  very  dilute  o-ives  an  immediate 
precipitate  of  butyrate  of  copper). 

e. — Separation. — Iso valeric  acid  is  separated  from  non-vola- 
tile matters,  and  obtained  from  its  salts,  by  distillation,  adding 
diluted  sulphuric  acid  if  necessary  to  liberate  it.  From  other 
volatile  acids  fractional  saturation  and  distillation  may  be  em- 
plo3Ted,  having  regard  to  boiling  points. — Separation  from  aqueous 
solutions  is  effected  by  ether  more  readily  than  by  distillation. 
The  aqueous  solution,  in  which  the  valeric  acid  is  liberated,  if 
need  be,  by  adding  potassium  bisulphate,  is  saturated  with  sodium 
sulphate  and  shaken  out  with  portions  of  ether. 

f. — Quantitative. — The  valeric  acids  may  be  estimated  volu- 
metrically  with  standard  solutions  of  alkali,  using  either  litmus- 
papers  or  phenol-phthalein  as  the  indicator  of  saturation.  Each 
c.c.  of  normal  solution  of  alkali  indicates  0.102  gram  of  real 
valeric  acid  ;  each  c.c.  decinormal  solution,  0.0102  gram.  And 
if  5.1  grams  of  material  be  taken,  c.c.  of  N  alkali  X  2  =  per. 
cent,  of  acid  ;  if  1.02  grams  be  taken,  c.c.  of  /^  =  per  cent. 

g. — Tests  of  Purity. — "  Purified  by  distillation,  valeric  acid 
is  a  colorless  liquid,  oleaginous,  of  a  peculiar  disagreeable  odor. 
It  dissolves  in  30  parts  of  water  at  20°  C.,  and  in  all  proportions 
of  alcohol  or  ether.  Its  specific  gravity  at  0°  C.  is  about  0.955. 
It  boils  at  175°  C."(Th.  Fran.) — "A  specific  gravity  above 
0.950,  and  solubility  in  less  than  25  parts  of  water,  indicates  pre- 
sence of  water,  acetic  or  butyric  acid,  amyl  alcohol  or  aldehyde. 
The  last  two  are  known  by  their  insolubility  in  ammonia-water. 
If  half  of  a  mixture  of  equal  parts  of  butyric  and  valeric  acids 
be  neutralized  with  alkali,  and  the  whole  distilled  together,  the 
butyric  acid  goes  over,  arid  will  be  found  soluble  in  not  above 
10  parts  of  water  "  (Fliickiger's  "  Phar.  Chera.") 

VAPOR  TENSION,  DETEKMINATION  OF.     See  p  237. 
VINEGAR.     See  ACETIC  ACID,  p.  14.-, 


INDEX. 


Abies  Canadensis,  tannin  of 481 

Absinthin 7 

Absinthin,  in  plant  analysis 425 

Acetate  of  lime 11 

Acetate  of  sodium 11 

Acetic  acid .    »  .7 

Acid  Azo-rubin 184 

Acid  Magenta 184 

Acid  Naphthol  Yellow 185 

Acids,    organic,   in  plant  analy- 
sis  415,419,  424 

Acid  tartrate  of  potassium 496 

Aconelline 387 

Aconine . . 18 

Aconite  assay 27 

Aconite  roots 19 

A  conitic  acid , 30 

Aconitic  acid  from  citric 86 

Aconite  alkaloids. ...   17 

Aconitine 17 

Aconitine  poisoning,  analysis  for.     28 
Aconitine,   saponification  of. ...     171 

Aconitines  of  commerce 30 

Aconitum,  aconitic  acid  in 30 

Aconitum,  species  of 19 

JEsculin 31 

Air-pump  for  combustions 222 

Albumens,  in  plant   analysis  . . 

416,.  420,  425 
Alcoholic  beverages,  analysis  of, 

for  strychnine 460 

Alcohols  in  fusel  oil 315 

Alder  tannin 481 

Ale,  analysis  of,  for  strychnine. .  460 

Alizarin 189,  197 

Alkali  blue 187 

Alkaloid*,  color-tests  of 50 

Alkaloids,  in  general „ 32 

Alkaloids,  in  plant  analysis.  .418,  424 
Alkaloids,  reagents  for 42 


Alkaloids,  separation  of 33 

Alkanet 194 

Alkanna-violet 194 

Alloxantin 80 

Alnus  glutinosa,  tannin  of 481 

Aloes  dye 188 

Aloes,  tests  for.    „ 56 

Aloes,  varieties 54 

Aloins • 54 

Amalic  acid. . .    80 

Amethyst 188 

Amido-azo-benzol 185 

Amido-succinamic  acid 58 

Amido-succinic  acid 58 

Amphicreatinine 428 

Arnygdalic  acid 57 

Amygdalin 56 

Amygdalin  in  color-tests  with  sul- 
phuric acid 50 

Amyl  alcohols 315 

Analysis,  inorganic  and  organic.  393 
Analytical  chemistry  of    carbon 

compounds 391 

Andromeda  Leschenaultii,  oil  of.  433 

Aniline  blue .187,  197 

Aniline  brown 197 

Aniline  dyes  with  immiscible  sol- 
vents.   195 

Aniline  dyes  in  inks. 482 

Aniline  green 194 

Aniline  orange 197 

Aniline  reds 189,  191,  197 

Aniline  violet 197 

Aniline  yellow 197 

Anisol-red 184 

Annatto 193 

Anthemis  nobilis 519 

Anthracene  oil,  a  fraction  from 

coal-tar 395 

Antipyrine 168 

521 


522 


INDEX. 


Apo-alkaloids  of  the  Aconites ...  19 

Apo-dicinchonine 91 

Apo-diquinidine. 91 

Apomorphine 390 

Apomorphine  in  color-tests  with 

sulphuric  acid 50 

Apomorphine  in  color-tests  with 

Froahde's  reagent 51 

Arbutin 57 

Archil 192 

Argols 496 

Aricine 92 

Arsenic,  qualitative  analysis  for. .  200 

Artemisia  absinthium 7,  518 

Ash,  estimation  of 410 

Asphalt,  a  fraction  from  coal-tar.  395 

Asparagm 58 

Aspartic  acid 58 

Atropine 344 

Atropine,  saponification  of 171 

Atropine,  tests  of  purity  of 357 

Auramin 185 

Auric  chloride  with  alkaloids 49 

Azo  color  compounds 186 

Azo  compounds  from  Lieber- 

mann's  test 516 

Azotometer,  Schiff's 221 

Baking-powders 500 

Baldriansaure 518 

Balsams  containing  cinnamic 

acid 69,  71 

Barbaloin 54 

Bebirine 58 

Beer,  analysis  of,  for  salicylic  acid  440 
Beer,  analysis  of,  for  strychnine.  460 
Beeswax,  melting  and  congealing 

points 271 

Belladonna,  alkaloids  of 340 

Belladonna  assay 351 

Belladonna  extract,  assay  of 353 

Belladonna  plasters,  assay  of 353 

Belladonna  root  or  leaves,  assay  of  351 

Bengal-red 183 

Benzene,  certain  derivatives  of. .  434 
Benzoates. .  62 


Benzofisaure 59 

Benzoic  acid 59 

Benzoic  acid,  tests  of  purity  of. . .     66 

Benzoin 59 

Benzoyl-ecgonine 170,  173 

Benzyl  fluorescein 185 

Berberine 71 

Betaine 428 

Biberine 58 

Bichromate,  for  combustions. . . .  210 

Biebrich  scarlet 184 

Bismarck  brown 186 

Bitartrate  of  potassium 496 

Bitter-almond  oil,  relation  to  ben- 
zoic  acid 60,  63 

Blue  coloring  matters 187 

Blue  inks 482 

Bohea 504 

Bone  fat,  sp.  gr.  and  melting  of . .  274 

Bordeaux  blue 184 

Borosalicylic  acid 438 

Boheatannic  acid , 481 

Boheic  acid 481 

Brazil-wood  color 193 

Brazil-wood  in  inks 482 

Bromine,  estimation  of 236 

Bromine,  qualitative  analysis  for.  200 
Bromine  reactions  with  alkaloids  47 

Brucine 463 

Brucine  in   color-tests  with  sul- 
phuric acid 50 

Brucine      in       color-tests     with 

B^roehde's  reagent 51 

Brucine    in   color-tests  with   ni- 
tric acid 52 

Brucine  separation  from  strych- 
nine, .o 458 

Butter 293 

Butter-analysis,  competence  of. . .  310 
Butter-analysis,  interpretation  of  300 

Butter,  artificial  colors  of 295 

Butter,  estimation  of  rancidity  of  295 

Butter-fat 298 

Butter-fat,  methods  of  analysis  of  300 
Butter,  microscopic  analysis  of. . .  297 
Butter,  odor- test  of 298 


INDEX. 


523 


Butter,  salicylic  acid  in 441 

Butter-soaps,  viscosity  of 297 

Butter  substitutes 300 

Butyric  acid 75 

Buxine 58 

Cacao  butter,  melting  of 269,  272 

Cadaveric  alkaloids 426 

Cadaverine 427 

Caffeine 77 

Caffeine  from  theobromine 514 

Caff etannic  acid 480 

Caffetannin 480 

Calcium  tartrate 498 

Camphors,  in  plant  analysis  ....  418 
Canned    fruits,    analysis  of,    for 

salicylic  acid 440 

Cantharides,  assay  of 84 

Cantharidin .  .     83 

Capric  acid 245 

Caproic  acid 245 

Caprylic  acid 245 

Capsicum,  in  plant  analysis 425 

Carbolates 398,  401 

Carbolic  acid 396 

Carbolic  acid,  as^ay  of 404 

Carbolic   oil,  as  a  fraction  from 

coal-tar 395 

Carbolsaure 396 

Carbon  and  Hydrogen  estima- 
tion  208,  219 

Carbon,  qualitati ve  analysis  for. .  198 
Carius's  method  for  halogens  or 

sulphur 236 

Caryophyllin,  in  plant  analysis. .  425 

Cascarilline,  in  plant  analysis 425 

Castor  oil 289 

Castor  oil,  melting  of  fat  acids  of  269 

Castor  oil,  tests  of  purity  of 290 

Catechin 479 

Catechutannic  acid 479 

Catechutannin 479 

Celandine,  constituent  of 84 

Cell  formation  not  a  direct  result 

of  chemism 391 


Cellulose,  in  plant  analysis,  417,  421, 

426 

Cevadine,  saponification  of . .  171 

Chairamidine 92 

Chairamine 92 

Cheese  poison 514 

Cheese  poison,  as  a  ptomaine. . . .  429 

Chelidonine 84 

Chestnut-red 482 

Chestnut  tannin 482 

Chinidine 154 

Chinin 125 

Chmoidine 94 

Chifioline 165 

Chinophtalon 185 

Chitenine 128 

Chloride  of  calcium,  for  analysis.  205 

Chloride  of  calcium  tubes 206 

Chlorine,  estimation  of 236 

Chlorine,  qualitative  analysis,  for  200 
Chlorophyll,  in  plant  analysis,  418,  424 

Chocolate  nut 512 

Choline 427 

Chromate  in  inks 482 

Chromate  of  lead,    for   combus- 
tions         203,  210 

Chrysammic  acid 56,  188,    •  97 

Chrysoidin 186 

Cider,  analysis  of,  for  salicylic  acid  440 

Cinchamidine 93 

Cinchona  Alkaloids 90 

Cinchona  alkaloids,   constitution 

of 97 

Cinchona  alkaloids,  yield  of 96 

Cinchona  assay 102 

Cinchona    barks,    alkaloidal 

strengths  of 96 

Cinchona  barks,  assay  of 102 

Cinchonamine 92 

Cinchonicine 91 

Cinchonidine 157 

Cinchonidine  salts 158 

Cinchonidine,  tests  of  purity  of.  159 

Cinchonine 161 

Cinchonine  salts. .  .  162 


524 


INDEX. 


Cinchonine,  tests  for  purity  of . . .  164 

Cinehotannic  acid 479 

Cinchotannin 479 

Cinchotine 93 

Cinnamates 69,  70 

Cinnamein 71 

Cinnamene 71 

Cinnamic,  acid 69 

Cinnamic  aldehyde. 69 

Cinnamon  oil,  relation  of 69 

Citracohic  anhydride 31 

Citrates 86 

Citric  acid 85 

Citric  acid,  tests  of  purity  of 89 

Citronensaure 85 

Citronin 186 

Coal-tar  distillation,   fractions 

from 395 

Coca  A  Ikaloids 170 

Cocaicine 112 

Cocaine.... 170,  174 

Cocaine  hydrochloride . .  174,  175,  180 

Cocaine  salts 174,  175 

Cocaine,  tests  for  purity  of 180 

Cocainoidine 170,  172 

Coca  leaves,  assay  of 178 

Cochineal 193 

Cochineal  violet 194 

Cocoa  nibs 513 

Cocoanut  oil,  melting  of 269,  274 

Cocoa  shells 513 

Codamine 359 

Codeine 388 

Coffee,  assay  of 81 

Coffee,  tannin  of 480 

Coffein 77 

Cola  nut,  assay  of 81 

Cola  nut,  theobromine  in 513 

Colchicine  in  color-test  with  sul- 
phuric acid ' 50 

Colchicine     in     color -test    with 

Froehde's  reagent 51 

Colchicine,  in  plant  analysis 425 

Colocynthin  in    color-tests  with 

Froehde's  reagent 51 

Colocynthin,  in  plant  analysis. . .  425 


Colombin  in  color-tests  with  sul- 
phuric acid. 50 

Coloring  Materials 181 

Coloring  matters  of  butter 295 

Color-reactions  of  the  alkaloids. .     50 

Colors,  in  plant  analysis 419 

Combustion-furnaces 208,  216 

Combustions,  analytical 201 

Combustion  tubing 206 

Conchairamidine 92 

Conchairamine 92 

Conchinine 154 

Concusconidine 93 

Concusconine 92 

Congo-red 184 

Conine  in  color-test  with  sulphu- 
ric acid 50 

Conquinamine 92 

Convallamerin,  in  plant  analysis. .  425 

Copper,  for  combustions  204 

Copper  oxide,  for  organic  combus- 
tions   202 

Coptis,  per  cent,  of  berberine  in . .     72 

Copying  inks 483 

Corallin 196,197 

Corallin  red '. 191 

Corulein 186,  196 

Cotarnine 360,  388 

Cotton-seed  oil 287 

Cotton-seed  stearin 289 

Cranberries,  constituent  of 85 

Cream.of  Tartar 496 

Creosote,  compared  with  carbolic 

acid 394,  401 

Creosote  oil,  of  coal-tar  distilla- 
tions   395 

Cresols. . .  394 

Cresol-sulphonic  acids 406 

Cresotic  acids 434,  443 

Cresylic  acid 394 

Crocein  scarlet 184 

Cruscocreatinine 428 

Cryptopine 360,  362 

Cryptopine  in  color-test  with  sul- 
phuric acid 50 

Crysolin 185 


INDEX. 


525 


Cubebin  in  color-tests  with  sulphu- 
ric acid. ...    50 

Cubebin,  in  plant  analysis 425 

Cuprea  barks,  constituents  of 92 

Cupreine 92 

Cupreine,  test  for 153 

•Curarine  in  color-test  with  sulphu- 
ric acid 50,  52 

Curarine  interference  with  strych- 
nine test 454 

Curcumin  dye 185 

Cusconine. 92 

Dalican's  method  for  fats 252 

Daphnin,  in  plant  analysis ...  425 

Dat  urine 340,  341,  344 

Dead  oils  of  coal-tar  distillations. .  395 
Deduction  of  chemical  formula. ..  237 

Delphinine,  in  plant  analysis 425 

Dextrines,  in  plant  analysis . .  420,  425 

Dextrotartaric  acid 485 

Diazobenzene  compounds 515 

Diazo  color  compounds 184 

Dichonchonine 91 

Dicinchonicine 91,  95 

Diconchinine 91 

Digallic  acid 474 

Digitalein,  in  plant  analysis 425 

Dihydroxyl-quinine 128 

Dimethyl-amido-azo  benzol 185 

Dimethyloxyquinizine 0 . . .  16i> 

Dimethylprotocatechuic  acid 18 

Dimethyl  xanthine 212 

Diphenylamine  yellow  . .  .<> 186 

Diquinicine 91,  95 

Dragendorff's     plan     for    plant 

analysis 423 

Dragendorffs    process    for    alka- 
loids   33 

Drying  oils 281 

Duboisia,  alkaloids  of 340 

Duboisine 340 

Ecgonine 170,  172 

Eisessig 8 

Elaidic  acid. .  ..,€47 


Elaidin  test 281 

Elateriri      in      color-tests     with 

Froehde's  reagent 51 

Elaterin  in  color- tests  with  sul- 
phuric acid 50 

Elaterin,  in  plant  analysis 425 

Elementary  analysis 198 

Elementary    analysis,    inorganic 

and  organic 392 

Elementary      organic     analysis, 

quantitative 201 

Eosins 183 

Bosin  scarlet 183 

Bricolin,  in  plant  analysis 425 

Erlenmeyer's  furnace 208 

Erythroxylon  Coca 170 

Essigsaure 7 

Essigsauren  Kalk 11 

Ethyl-orange 186 

Extraction  apparatus 409 

Extraction-apparatuses  for  liquids 

(illustrated) 38 

Extract  of  belladonna,  assay  of. . .  353 
Extract  of  nux-vomica,  assay  of..  457 

Fat  acids,  percentages  of,  insol- 
uble    256 

Fat  acids,  quantitative  determina- 
tions of 250 

Fat  oils,  specific  gravity  of 262 

Fats  and  Oils 238 

Fatty  acid  series 239,  245,  246 

Filter  of  Gooch 409 

Flavanilin 185 

Fleischer's  estimation  of  tartaric 

acid 495 

Formic  acid 312 

Formulas,  deduction  of 237 

Froehde's  reagent  for  alkaloids ...     51 
Fruits,    percentage  of  citric  acid 

in 85 

Fusel  oil 314 

Fustic  color 193 

Fustic  tannin 479 

Gadinine..  .  427 


526 


INDEX. 


Gallein 183 

Gallic  acid 320 

Gallic  anhydride 474 

Gallo-cyanin 188 

Q-allotannin 474 

Gaseous  bodies,  organic  combus- 
tions of 216 

Gaulthoria,  oil'of 433 

Geisler's  report  on  teas 505 

Gelseminine  in  color-test  with  sul- 
phuric acid .  50 

Gelseminine  in  color-test  with  ni- 
tric acid 52,  454 

Gelsemine,  in  plant  analysis 425 

Gerbsauren 465 

Gerland's  method  for  estimating 

tannins 471 

Gerrard's  test  for  atropine 348 

Glacial  acetic  acid 8, 14 

Glaser's  combustion  furnace 216 

Glucose,  in  plant  analysis. .  .415,  419, 

425 

Glucosides,  in  plant  analysis.. 413,  419, 

424 

Glucoside-tannins 466 

Glycerides,  as  a  chemical  class. . .  238 

Glycerin 323 

Glycerin,  tests  of  purity  of 328 

Gnoscopine 360 

Gnoscopine  in  color-test  with  sul- 
phuric acid 50 

Gold  chloride  with  alkaloids 49 

Gooch's  filter 409 

Gratiolin,  in  plant  analysis 425 

Green  Coloring  Matters 186,  193 

Green  oil  or  anthracine  oil 395 

Guarana,  assay  of 81 

Guaranine 77 

Gums,  in  plant  analysis 416,  420 

Hager's  method  for  estimating 
tannins 472 

Halogens,  estimation  of 236 

Hammer's  method  for  estimating 
tannins 473 

Hard  pitch 395 


Hectographic  ink 483 

Hehuer's  method  for  fats 250 

Hehner's  number,  interpretation 

of 301 

Helleborin,  in  plant  analysis 425 

Hemepic  acid 362 

Hemlock  bark,  tannin  of 481 

Hempseed  oil,  drying  test  of 282 

Helvetia  green 187 

Herapathite 131 

Hesse's  test  for  quinine  sulphate..  151 

Hippuric  acid  in  urine 62 

Hippuric  acid,  source  of  benzoic..     60 

Hof mann's  violet 188 

Holzessigsauren  Kalk 11 

Homatropine 343 

Homocinchonidine 93 

Homoquinine 92 

Hop  bitter,  in  plant  analysis. ,  . .  425 

Hop-tannin  481 

Hiibl's  method  with  fats 258 

Humus,  in  plant  analysis 417,  420 

Hydrastine 329 

' '  Hydrastine,"  yellow  alkaloid ...     72 

Hydrastis,  assay  of 74 

Hydrastis,  constituent  of 72 

Hydrocinchonidine  91 

Hydrocinchonine 93 

Hydroconquinine 93 

Hydrocotarnine 360,  362 

Hydrocyanic  acid,  from  amygda- 

lin 57 

Hydrogen,  estimation  of 208 

Hydrogen,     qualitative    analysis 

for 198 

Hydroquinidine 91 

Hydroquinine 91 

Hydroxy-benzoic  acids 433,  443 

Hydroxy-xylenic  acids 443 

Hygrine 170,  173 

Hyoscine 342 

Hyoscyamine 34£ 

Hyoscyamus,  alkaloids  of 340 

Hyoscyamus  assay 353 

Hyoscyamus    leaves    and    seeds, 

assay  of 353 


INDEX. 


527 


Hypogaic  acid 246,  249 

Igasurine 446 

Immiscible  solvents 33 

Inactive  valeric  acid 518 

Indelible  inks 483 

India-ink 482 

Indigo-blue 192 

Indigo-carmine 188 

Induline  R 188 

Inks 482 

Ink-stains,  discharge  of 484 

Inorganic  analysis,  relations  to 

organic 393 

Inorganic  substances,  in  organic 

analysis 200 

Inulin,  in  plant  analysis 425 

Iodine  and  methyl  green 1$7 

Iodine,,  estimation  of 236 

Iodine  numbers  of  fats 258 

Iodine,  qualitative  analysis  for. . .  200 
Iodine  reactions  with  alkaloids ...  42 

lodophenin 187 

Iron-bluing  tannins 466 

Iron-greening  tannins 466 

Isobutyl-carboxyl 518 

Isobutyric  acid  (foot-note) 75 

Isovalerates(isovalerianates) 519 

Isovaleric  (isovalerianic)  acid 518 

Itaconic  acid .  31 

Japaconine 18 

Japaconitine - 18 

Jaune  N 186 

Jervine  in  color-test  with  sulphu- 
ric acid ...  50 

Johnson  and  Jenkins's  method . . .  220 

Kairines 167 

Kerner's  test  for  quinine,  139, 144, 146 
Kjeldahl's  method  for  nitrogen . . .  234 

Koffein 77 

Kottstorfer's  method  for  fats 254 

Kottstorfer's  number,  interpreta- 
tion of 304 

Lanthopine 360,  362 


Lard 290 

Lard  oil 292- 

Lard,  tests  of  purity  of 291 

Laudanine 360,  362 

Laudanosine 360,  362 

Laudanum  assay 385 

Laurie  acid 245 

Laut's  violet.  „ 188 

Lead  chromate,  for  organic  analy- 
sis   203 

Lees  of  tartar 496 

Lemon-juice,  assay  of 89 

Leucoline 165 

Leucomaines 428 

Leukindophenol 188 

Lichen-red 192 

Liebig's  test  for  quinine 151 

Light  oil,  of  coal-tar  distillations. .  395 
Lignose,  in  plant  analysis. .  .418,  420, 

426 

Lime-juice 85,  89 

Linoleic  acid 249 

Linoxyn 249 

Linseed  oil 284 

Linseed  oil,  tests  of  purity  of 284 

Liquids,  organic  combustions  of..  213 
Liver,  excretion  of  aconite  alka- 
loids in 29 

Liver,  excretion  of  morphine  in. .  372 
Liver,  excretion  of  strychnine  in. .  450 

Lobeline,  in  plant  analysis 425 

Logan  in 447 

Logwood  blue 192 

Logwood  in  inks 482 

Lowenthal's  method  of  estimating 

tannins 468 

Luteolin 186 

Mace  oil,  melting  of 269,  272,  274 

Madder  colors 189 

Madder-red 193 

Madder-violet 194 

Magdala-red 182 

Magenta 183 

Malachite  green. . . , 187 

Malic  acid. .  .  333 


528 


INDEX. 


Manchester  brown 186 

Margaric  acid   244 

Martin's  yellow 185 

Mate,  assay  of ,     81 

Mauvein 188 

Mayer's  solution 43 

Mean    molecular   weight  of    fat 

acids 261 

Meconic  acid 337 

Meconic  acid,  as  analytical  proof 

of  opium 370 

Meconidine 360 

Meconidine  in  color-test  with  sul- 
phuric acid 50 

Meconin 362 

Meissl's  method  for  fats 253 

Melting  and  congealing  points  of 

fats 265 

Menyanthin,  in  plant  analysis . . .  425 

Metacresol 394 

Metatungstic  acid  with  alkaloids    43 

Metaxylenols 394 

Methylene  blue 187 

Methyl-orange 186 

Methyl-theobromine 77 

Microscopical    characteristics    of 

alkaloids 53 

Microscopical  distinctions  of  cin- 
chona alkaloids 101 

Microsublimation  of  alkaloids 53 

Middle  oil,  in  coal-tar  distillation  395 

Midriatic  alkaloids 339 

Milk,  examination  of,  for  salicylic 

acid 440 

Mineral  oils,  separation  from  gly- 

cerides. 274 

Molecules    as    final    products  of 

chemism 391 

Morintannic  acid 479 

Morintannin 479 

Morphine 362 

Morphine  in   color-test  with    sul- 
phuric acid 50 

Morphine     in      color-test      with 

Froehde's  reagent 51 

Morphine,  salts  of 364,  365 


Morphine,  tests  of  purity  of 386 

Moms  tinctoria 479 

Murexid 80 

M  urexoin 80 

Murexoin  test  for  theobromine . . .  513 

Muscarine 427 

Mygdalein  427 

Myristic  acid 245 

Mytilotoxine 428 

Narceine 359,  362 

Narceme  in  color-test   with  sul- 
phuric acid 50 

Narceine  in  color-test  with  nitric 

acid.. 52 

Narcotine 387 

Narcoline  in   color-test  with  sul- 
phuric acid 50 

Narcotine  in  color-test  with  nitric 

acid.. ' 52 

Neuridine  427 

Neurine ..427,428 

Nitrogen  and  carbon,  relative  de- 
termination   ! . ..  233 

Nitrogen  estimation 220,  229,  230, 

233;  234 
Nitrogen,  total,  in  plant  analysis . .  411 

Nitrosalicylic  acids 438 

Nutgails  in  inks 482 

Nutgalls,  treated  for  preparation 

of  tannic  acid 477 

Nutgall-tannin ...  474 

Nutmeg  oil,  melting  of 269,  272 

Nux-vomica,  alkaloids 447 

Nux-vomica,  assay  of  456 

Oak-bark  tannin 478 

Oils  and  fats  233 

Oil  of  birch 433 

Oils,  fixed 238 

Oils,  fixed,  in  plant  analysis.  ..418.  424 
Oils,  volatile,  in  plant  analysis. .  .412, 

423 

Olive  oil,  tests  of  purity  of 285 

Opianic  acid 362,  388 

Opium  alkaloids 358 

Opium  assay ^ 374 


INDEX. 


529 


Orcein 192 

Organic  analysis,  divisions  of. ...  391 

Organic  matter 391 

Orseille 192 

Oxalate  of  calcium,  in  plant  analy- 
sis   426 

Oxygen,  direct  estimation  of.    ...  234 

Oxymorphine 359 

Naphthalene-Carmine 182 

Naphthalene,   source   of    benzoic 

acid 60 

Naphthalene-Yellow 185 

Nataloin 54 

Nitric  acid  reactions  with  alka- 
loids      51 

Nitrogen,  qualitative  analysis  for..  199 

Okie  acid 246 

Olein 246 

Oleomargarin 292 

Olive-kernel  oil 287 

Olive  oil 285 

Opium  alkaloids 358 

Opium,  assay  of 374 

Orange  II 186 

Orange  G 186 

Oranges,  constituent  of 85 

Otto's  process  for  alkaloids 33 

Oxalic  acid,  separation  from  fruit 

juices 336 

Oxygen  gas,  for  organic  combus- 
tions   202 

Oxylinoleic  acid 249 

Palmitic  acid 244 

Palm  oil,  melting  and  congealing 

of.. 269,  274 

Papaverine 359,  362 

Papaverine  in  color-test  with  sul- 
phuric acid 50 

Papaver  somniferum 358 

Paracresol 394 

Paraffin,  melting  and  congealing. .  272 
Paraffins,   separation  from  glyce- 

rides 274 

Paratartaric  acid..  .432 


Paraxylenol 394 

Paricine 93 

Par  sons' s  plan  for  plant  analysis. .  408 

Pathological  tannins 467 

Paulinia,  constituent  of 77 

Paytamine 93 

Paytine 92 

Peanut  oil,  melting  of 269,  274 

Pectous  substances,  in  plant  analy- 
sis  416,  420,  421,  425 

Pe7<oe 504 

Pelosin 58 

Pentoic  acids 518 

Ferkin's  method  for  fats 255 

Perkin's  violet 188 

Persian  berries 193 

Phenol 393 

Phenols 394 

Phenolsulphuric  acid  and  its  salts  405 

Phenyl-acrylic  acid 69 

Pheny lene  brown 186 

Phenylsulphuric  acid  (foot-note) . .  406 
Phenylsulphuric  acid  in  the  urine  402 
Phlobaphene,  in  plant  analysis. . .  424 
Phloridzin  in  color-tests  with  sul- 
phuric acid 50 

Phloxin 183 

Phosphine 185 

Phosphomolybdates 46 

Phosphorus,  qualitative  analysis' 

for 199 

Physalin,  in  plant  analysis 425 

Physetoleic  acid 246,  250 

Physiological  tannins 467 

Physostigmine  in  color-test  with 

sulphuric  acid 50 

Physostigmine  in  color-test  with 

nitric  acid  52 

Physostigmine,  in  plant  analysis. .  425 

Phytochernical  analysis 407 

Picraconitine 18 

Picric  acid 398 

Picric  acid  with  alkaloids 48 

Picric  acid,  in  scheme  of  color  an- 
alysis   185 

Picro toxin,  in  plant  analysis 425 


530 


INDEX. 


Pilocarpine,  in  plant  analysis. . . .  425 

Pineapple  essence 75,  76 

Piperine,  in  plant  analysis 425 

Piperine,  saponification  of 171 

Pitch,  a  residue  of  coal-tar  distil- 
lation   395 

Piturine 341 

Plant  analysis 407 

Plasters  of  belladonna,  analysis  of  353 
Platinic  chloride  with  alkaloids. .  49 
Poisoning  by  alkaloids,  analyses 

for 33 

Poisoning  by  atropine,  analysis  for  354 
Poisoning  by  carbolic  acid,  analy- 
sis for  402 

Poisoning  by  morphine,  analysis 

for 370 

Poisoning  by  strychnine,  analysis 

for 458,449 

Poisons,  ptomaines  in  analysis  for, 

427,  429 

Ponceau  R 184 

Poppy  oil,  drying  of 282 

Populin  in  color-tests  with  sulphu- 
ric acid 50 

Populin,  in  plant  analysis 425 

Potash-bulbs 207 

Potash  solution,    for  elementary 

analysis 205 

Potassium  bismuth  iodide 47 

Potassium  cadmium  iodide 47 

Potassium  diazobenzene 517 

Potassium  mercuric  iodide 42 

Printer's  ink 483 

Protocatechuic  acid  formed  from 

tannins 466 

Protopine 360,  362 

Proximate  analysis,  inorganic  and 

organic 392 

Prussian  blue 192 

Pseudaconine 18 

Pseudacoriitine 18 

Pseudomorphine 359,  362 

Pseudoxanthine 428 

Ptomaines 426 

Puree 186 

Purpurin 190 


Purpurogallin 481 

Putrescine 427 

Pyridine  type  of  alkaloids.  .340,  97,  171 

Pyrogallic  acid 430 

Pyrogallol 430 

Pyrogallol  formed  from  tannins. .  466 

Pyrogallol-phthalein 183 

Pyrolignate  of  lime 11 

Quassin,  in  plant  analysis 425 

Quercitannic  acid 478 

Quercitrin 193 

Quinamicine „ . . .     92 

Quinamidine 92 

Quinamine 92 

Quinicine 91 

Quinidamine 92 

Quinidine 154 

Quinidine  salts 155 

Quinidine,  tests  of  purity  of 156 

Quinine 125,  148 

Quinine,  assay  of 139 

Quinine  bisulphate 127,  129,  149 

Quinine  hydrates 126,  128,  148 

Quinine  hydrobromide...  127,  129,  147 
Quinine  hydroehloride...  127,  129,  147 

Quinine  oxalate 127,  129 

Quinine  Pills,  assay  of 134 

Quinine  sulphate 126,  129,  139 

Quinine  tannate 129 

Quinine  tartrate 127,  129 

Quinine,  tests  of  purity  of J34 

Quinine  valerianate 127,  129,  147 

Quinoidine 94 

Quinoline 165 

Quinoline-red 182 

Quinoline  salts 166 

Quinoline  type  in  structure  of  al- 
kaloids      97 

Quinoline  yellow ' 185 

Racemic  acid 432 

Rancidity  of  butters 295 

Rape  oil,  melting  of  fat  acids  of. .  269 

Reagents  for  alkaloids 42 

Red  coloring  matters 182,  188,  193 

Red  inks..  ..  482 


INDEX. 


531 


Red  oil  or  anthracene  oil 395 

Regina  purple . .    . .   188 

Reichert's  method  for  fats 253 

Reichert's  number,  interpretation 

of 302 

Remijia  barks,  constituents  of . . .     92 

Resinoils 280 

Resins,  in  plant  analysis 418,  424 

Resins,  separation  from  glycerides  274 

Rhodidine 183 

Rhoeadine 360 

Rhoeagenine 360 

Ricinoleic  acid 248 

Roccellin 184 

Rochleder's  method  of  plant  an- 
alysis   407 

Rosaniline  blue 187 

Rosaniline  salts 183 

Rosin  oils 280 

Rosin,  separation  from  soaps ....  274 
Rotatory  power  of  cinchona  alka- 
loids   121 

Ruffle's  method  for  nitrogen 233 

Sabadilline  in  color-test  with  sul- 
phuric acid 50 

Sabadilline  in  color-test  with  nitric 

acid 52 

Sabadilline,  in  plant  analysis. . . .  425 

Sabatrine,  in  plant  analysis 425 

Safflower 189 

Safflower-red 191 

Saffranin  class  of  colors 183 

Saffranisol 183 

Saffron-carmine 193 

Salicin  in  color-tests  with  sulphu- 
ric acid 50 

Salicin      in       color-tests      with 

Proehde's  reagent 51 

Salicin,  in  plant  analysis 425 

Salicylates 437 

Salicylic  acid 433 

Salicylic  acid,  tests  of  purity  of. .  442 

Salicyl-sulphonic  acid 439 

Salicyluric  acid 445 

Sandal. 189,  191 


Santonin,  in  plant  analysis 425 

Saponification  coefficients 257 

Saponin,  in  plant  analysis 425 

Saprine 427 

Sarsaparillin   in  color-tests  with 

sulphuric  acid 50 

Schiff 's  azotometer 221 

Senegin  in  color-test  with  sulphu- 
ric acid  50 

Senegin,  in  plant  analysis 425 

Separators,    for    alkaloidal    solu- 
tions (illustrated) 35 

Sesame  oil,  melting  of 269,  274 

"  Shaking  out"  of  alkaloidal  solu- 
tions      33 

Simpson's  method  for  combustions  227 

Sinking  point 265 

Smilacin  in  color-test  with  sulphu- 
ric acid 50 

Socaloin 54 

Soda-lime,  for  organic  analysis. . .  204 
Soda-lime  process  for  nitrogen. . .  230 

Soft  pitch 395 

Solanaceae,  alkaloids  of 339 

Solanidin,  in  plant  analysis 424 

Solanine  in  color-test  with  sul- 
phuric acid 50 

Solanine,  in  plant  analysis 425 

Souchong 504 

Sparteine,  in  plant  analysis 425 

Specific  gravity  of  fats 261 

Specific-gravity  tests  for  butters. .  305 

Stains  of  ink,  discharge  of 484 

Starch,  in  plant  analysis .  .417,  420,  426 
Starch  isomers,  in  plant  analysis . .  421 

Stas's  process  for  alkaloids 33 

Stearic  acid 240 

Stearicand  palmitic  acid,  melting 

points  of 267,  272 

Stearin  240,  243 

Sterculia  acuminata 513 

Storax,  constituents  of 71 

Strarnmonium,  alkaloids  of 340 

Strychnine 447 

Strvchnine  salts. .  .  443 


532 


INDEX. 


Strychnine  separation  from  bru- 

cine 458 

Strychnos  alkaloids 446 

Styracin 71 

Subliming  Cell  for  alkaloids 53 

Sucrose,  in  plant  analysis. .  .415,  419, 

425 
Sugar?,  in  plant  analysis.. 415,  419,  425 

SulpTiocarbolates 405 

Sulphophenates 406 

Sulphur,  estimation  of 236 

Sulphuric  acid  reactions  with  al- 
kaloids  50,  52 

Sulphuric-acid  reactions  with  glu- 

cosides 50 

Sulphur,  qualitative  analysis  for. .  199 

Sumach  tannin 477 

Sunflower-seed  oil,  melting  of  fat 

acids  of 269 

Syringin   in  color-test  with  sul- 
phuric acid 50 

Syringin,  in  plant  analysis ;  425 

Tallow  oil 1 292 

Tannic  acid 474 

Tannic  acid  reactions  with  alka- 
loids      48 

Tannic  acids  (Tannins). 465 

Tannic  acids  in  color-tests  with 

sulphuric  acid 50 

Tanning  materials 466 

Tannin  of  hemlock  bark 481 

Tannin  of  hops 481 

Tannin  of  tea 480,  504,  506,  510 

Tannins 465 

Tannins,  estimation  of .468 

Tannins,  in  plant  analysis 415,  424 

Tar  oils,  estimation  in  crude  car- 
bolic acid 403 

Tartaric  acid 485 

Tartaric-acid  estimation 489 

Tartaric  acid,  inactive 432 

Tartaric  acid  separation  from  fruit 

juices 336 

Tartars 496 

Tartrate  of  calcium..  .  498 


Tartrates 489 

Taxine,  in  plant  analysis 42") 

Tea,  assay  of 81 

Tea  infusions 509 

Teas,  black  and  green 504 

Teas  of  commerce .   504 

Tea,  tannin  of 480,  504  6 

Thalleioquin , 130 

Thalline 163 

Thea  plant 504 

Thebaine 358,  362 

Thebaine  in  color-test  with  sul- 
phuric acid 50 

Thebaicine 359 

Thebenine 359 

Theine 77 

Theobroma  cacao . .  512 

Ttieobromine 512 

Thiosulphate  method  for  nitrogen  233 
Toluene,  source  of  benzoic  acid. .     60 

Toluylene-red 183 

Toxicology  of  aconite  alkaloids.. 28,  24 
Toxicology  of  alkaloids  in  general 

33,  42 

Toxicology  of  atropine 354,  345 

Toxicology  of  belladonna 340,  354 

Toxicology  of  carbolic  acid 402 

Toxicology  of  "cheese  poison". . .  514 

Toxicology  of  fusel  oil 318,  316 

Toxicology  of  morphine 370 

Toxicology  of  ptomaines 427,  429 

Toxicology  of  strychnine 458,  449 

Trimethylamine,  in  plant  analysis  425 
Trimethylamine,  with  ptomaines..  427 

Tropeines 339 

Tropic  acid 339,  349 

Tropines 339,  349 

Tropceolin  0 1 86 

Tropceoline-yellow 186 

Turkey-red  oil 287 

Turmeric. . . 193 

Tyrotoxicon 514 

Ultimate  analysis,  inorganic  and 

organic 392 

Ultimate,  organic  analysis 201 


INDEX. 


533 


Uric  acid,  test  of 80 

Urine,  analysis  of,  for  aconitine 

28,29 

Urine,  analysis  of,  for  atropine . . .  355 
Urine,  analysis  of;  for  carbolic 

acid 402 

Urine,  analysis  of,  for  strychnine  460 
Urine,  excretion  of  aconitine  in . .  29 
Urine,  excretion  of  atropine  in ...  346 
Urine,  excretion  of  benzoic  acid . .  62 
Urine,  excretion  of  carbolic  acid  402 
Urine,  excretion  of  cinnamic  acid  70 
Urine,  excretion  of  morphine  in . .  372 

Urine,  excretion  of  quinine 128 

Urine,  excretion  of  salicylic  acid 

in 436 

Urine,  excretion  of  strychnine  in  449 

Valerates  (valerianates) 519 

Valeriana  officiualis 518 

Valerian  root 518 

Valeric  (valerianic)  acids 518 

Varentrapp  and  Will's  method. .  230 

Veratrine,  saponification  of 171 

Veratrine  in  color-test  with  sul- 
phuric acid 50 

Veratrine  in  color-test  with  nitric 

acid 52 

Veratroidine  in    color-test    with 

sulphuric  acid. 50 

Vesuvin 186 

Vesuvin-brown .  105,  195 

Viburnum  opulus 519 

Victoria-blue 187 

Victoria-green 187 

Vinegar  assay 15 

Vinegars 14 


Violet  coloring  matters 188,  194 

Viscosity  of  butter  soaps 297 

Vi tali's  test  for  atropine 347 

Volatile  oils,  in  analysis  of  plants 

412,  423 

Wagner's  method  for  estimating 

tannins 473 

Walnut  oil,  drying  of 282 

Wanklyn's  method  for  nitrogen..  234 
Warren's  method  of  combustions  214 
Warrington's  estimation  of  tartar- 

ic  acid 491 

Water-blue 187 

Water- washed  solvents 34 

Waxes,  in  plant  analysis 418 

Waxes,  separation  from  glycerides  274 

Weinsaure 485 

Weld 193 

Wine,  analysis  for  salicylic  acid . .  440 

Wintergreen  oil. . .,. 433 

Wittstein's  plan  for  plant  analysis  407 
Wool  fat,  melting  of  fat  acids  of..  269 

Wormwood 7 

Writings,  chemical  examination  of  483 

Xanthine „ 77 

Xanthine,  dimethyl 512 

Xanthocreatinine 428 

Xanthoxylum,  constituent  of .     72 

Xylenols 394 

Xylol-sulphonic  acids 406 

Yellow  and  orange  coloring  matters  184 
Yellow  coloring  matters 192 


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10  D.  VAN  NOSTRAND  COMPANY'S 

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12  D.  VAN  NOSTRAND  COMPANY'S 


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HALL,  WM.  S.   Prof.      Elements  of  the  Differential 

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HALSEY,  F.   A.    Slide  Valve  Gears,  an  Explanation 

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SCIENTIFIC  PUBLICATIONS.  13 


HAMILTON,  W.  G.    Useful  Information  for  Railway 

Men.  Tenth  Edition,  revised  and  enlarged.  562  pages,  pocket 
form.  Morocco,  gilt $2.00 

HANCOCK,  HERBERT.    Text-Book  of  Mechanics  and 

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HARJIISON,    W.    B.      The    Mechanics'    Tool    Book. 

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HASKINS,    C.   H.      The   Galvanometer  and  its   Uses. 

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HAWKE,  WILLIAM  H.  The  Premier  Cipher  Tele- 
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HAWKINS,  C.  C.,  and  WALLIS,  F.      The  Dynamo; 

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HAY,    ALFRED.      Principles    of  Alternate  -  Current 

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HEAVISIDE,    OLIVER.        Electromagnetic    Theory. 

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HURST,   GEORGE   H.      Lubricating  Oils,    Fats    and 

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SCIENTIFIC  PUBLICATIONS.  15 


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500  illustrations.  Third  Edition,  carefully  revised  and  much  en- 
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The    Works'    Manager's    Hand-Book  of   Modern 

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INNES,  CHARLES  H.    Problems  in  Machine  Design, 

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ISHERWOOD,  B.  F.  Engineering  Precedents  for  Steam 

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JAMESON,   CHARLES    D.      Portland  Cement.      Its 

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JAMIESON,  ANDREW,  C.E.    A  Text-Book  on  Steam 

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JANNETTAZ,  EDWARD.    A  Guide  to  the  Determina- 

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KANSAS  CITY  BRIDGE,  THE     With  an  Account  of 

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KAPP,  GISBERT,  C.E.  Electric  Transmission  of  Ener- 
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Dynamos,  Alternators  and  Transformers.  138  Illus- 
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KEMPE,   H.    R.      The    Electrical    Engineer's    Pocket 

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KENNELLY,  A.  E.  Theoretical  Elements  of  Electro- 
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KILGOUR,  M.  H.,  SWAN,  H.,  and  BIGGS,  C.  H.  W.  Elec- 
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KING,  W.  H.    Lessons  and  Practical  Notes  on  Steam. 

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KINGDON,  J.  A.  Applied  Magnetism.  An  introduc- 
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KIRKALDY,   Wm.   G.    Illustrations  of  David  Kirk- 

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KIRKWOOD,   JAS.   P.     Report    on   the    Filtration   of 

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LARRABEE,  C.  S.  Cipher  and  Secret  Letter  and  Tele- 
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SCIENTIFIC  PUBLICATIONS.  17 


LEASK,  A.  RITCHIE.      Breakdowns  at  Sea  and  How 

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Triple  and    Quadruple    Expansion    Engines    and 

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Refrigerating  Machinery:  Its  Principles  and  Man- 
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LECKY,  S.  T.  S.    "  Wrinkles  "  in  Practical  Navigation. 

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LEITZE,   ERNST.      Modern    Heliographic  Processes. 

A  Manual  of  Instruction  in  the  Art  of  Reproducing  Drawings,  En- 
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specimens  of  Heliograms.  8vo,  cloth.  Second  Edition. .  

LEVY,   C.   L.    Electric  Light  Primer.    A  Simple  and 

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safety.  For  the  use  of  persons  whose  duty  it  is  to  look  after  the 
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LOCKE,  ALFRED  G.  and  CHARLES  G.     A  Practical 

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LOCKERT,    LOUIS.      Petroleum    Motor-Cars.    ISmo, 

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LOCKWOOD,  THOS.  D.     Electricity,  Magnetism,  and 

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Electrical  Measurement  and  the  Galvanometer ;  Its 

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LODGE,  OLIVER  J.  Elementary  Mechanics,  includ- 
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LUCE,   Com.   S.   B.      Text-Book  of  Seamanship.    The 

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LUNGE,  GEO.     A  Theoretical  and  Practical  Treatise 

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LUNGE,  GEO.,  and  HURTER,  F.    The  Alkali  Maker's 

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LUQUER,  LEA  McILVAINE,   Ph.   D.      Minerals  in 

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MAGUIRE,  Capt.   EDWARD,  U.  S.  A.      The  Attack 

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MAGUIRE,  WM.   R.        Domestic  Sanitary  Drainage 

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MAYER,   Prof.   A.   M.      Lecture   Notes    on  Physics. 

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McNEILL,   BEDFORD.      McNeill's  Code.      Arranged 

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MERRILL,  Col.  WM.  E.,  U.S.A.     Iron  Truss  Bridges 

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METAL  TURNING.     By  a  Foreman  Pattern  Maker. 

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MINIFIE,  WM.  Mechanical  Drawing.    A  Textbook  of 

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MOREING,  C.  A.,  andNEAL,  THOMAS.     Telegraphic 

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MORRIS,  E.    Easy  Rules  for  the  Measurement  of  Earth- 
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MOSES,  ALFRED  J.,  and  PARSONS,  C.  L.     Elements 

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MOSES,   ALFRED    J.      The  Characters  of   Crystals. 

An  Introduction  to  Physical  Crystallography,  containing  321  Illustra- 
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MOELLER,   F.   C.    G.      Krupp's  Steel  Works.     With 

88  illustrations.  By  Felix  Schmidt  and  A.  Montan,  Authorized 
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MULLIN,  JOSEPH  P.,  M.E.      Modern  Moulding  and 

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MUNRO,   JOHN,  C.E.,  and  JAMIESON,  ANDREW, 

C.  E.  A  Pocketbook  of  Electrical  Rules  and  Tables  for  the 
use  of  Electricians  and  Engineers.  Thirteenth  edition,  revised 
and  enlarged.  With  numerous  diagrams.  Pocket  size.  Leather.  $2. 50 

MURPHY,  J.  G.,  M.E.      Practical  Mining.     A  Field 

Manual  for  Mining  Engineers.  With  Hints  for  Investors  in  Mining 
Properties.  16mo,  morocco  tncks $1.00 

NAQTJET,  A.  Legal  Chemistry.  A  Guide  to  the  Detec- 
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and  Pharmaceutical  Substances,  Analysis  of  Ashes,  and  examination  of 
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Translated,  with  additions,  including  a  list  of  books  and  memoirs  on 
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preface  by  C.  F.  Chandler,  Ph.D.,  M.D.,  LL.D.  12mo,  cloth.  .$2.00 

NASMITH,  JOSEPH,    The  Student's  Cotton  Spinning. 

Third  edition,  revised  and  enlarged.  8vo,  cloth,  622  pages,  250 
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NEWA.LL,  JOHN  W.     Plain  Practical  Directions  for 

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NEWCOMB,  EDWARD  W.  Stepping  Stones  to  Pho- 
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NEWLANDS,  JAMES.    The  Carpenters'  and  Joiners' 

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sary of  Terms  used  in  Architecture  and  Building.  Illustrated.  Folio, 
half  mor $15.00 

NIPHER,   FRANCIS  E.,  A.M.      Theory  of  Magnetic 

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NOAD,    HENRY    M.      The   Students'  Text  Book  of 

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NUGENT,  E.   Treatise  on  Optics;   or,  Light  and  Sight 

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O'CONNOR,   HENRY.      The  Gas   Engineer's    Pocket 

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SCIENTIFIC  PUBLICATIONS.  21 


OSBORN,  FRANK  C.     Tables  of  Moments  of  Inertia, 

and  Squares  of  Radii  of  Gyration;  Supplemented  by  others  on  the 
Ultimate  and  Safe  Strength  of  Wrought  Iron  Columns,  Safe  Strength 
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OSTERBERG,  MAX.    Synopsis  of  Current  Electrical 

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1895.  8vo,  cloth $1.00 

OUDIN,  M.  A.      Standard  Polyphase  Apparatus  and 

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PAGE,  DAVID.  The  Earth's  Crust,  A  Handy  Out- 
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PALAZ,  A.,  ScD.  A  Treatise  on  Industrial  Photome- 
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revised.  8vo,  cloth.  Illustrated $4.00 

PARSHALL,  H.  F.,  and  HOB  ART,  H.  M.     Armature 

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PARSHALL,  H.  F.  Electrical  Equipment  of  Tram- 
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PEIRCE,   B.      System    of  Analytic    Mechanics.    4to, 

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Linear  Associative  Algebra.    New  edition  with  addenda 

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PERRINE,  F.  A.  C.,  A.  M.,  D.  Sc.  Conductors  for  Elec- 
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other  Uses In  Press. 

PERRY,  JOHN".      Applied  Mechanics.      A  Treatise  tor 

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PHILLIPS,    JOSHUA.      Engineering    Chemistry.     A 

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PICKWORTH,  CHAS.  N.      The  Indicator  Hand  Book. 

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22  D.  VAN  NOSTRAND  COMPANY'S 


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PLANE  TABLE,  The.  Its  Uses  in  Topographical  Sur- 
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PL  ANTE,  GASTON.     The  Storage  of  Electrical  Energy, 

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PL  ATTNER.     Manual  of  Qualitative  and  Quantitative 

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PLYMPTON,  Prof  GEO.  W.    The  Blow-Pipe.   A  Guide 

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POOLE,   JOSEPH.     The   Practical   Telephone   Hand- 

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POPE,  F.  L.  Modern  Practice  of  the  Electric  Tele- 
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illustrated.  8vo,  cloth $1.50 

POPPLEWELL,  W.  C.     Elementary  Treatise  on  Heat 

and  Heat  Engines.  Specially  adapted  for  engineers  and  students  of 
engineering.  12mo,  cloth,  illustrated $3.00 

POWLES,   H.  H.     Steam  Boilers (In  Press.) 


SCIENTIFIC  PUBLICATIONS.  23 


PRAY,  Jr.,  THOMAS.  Twenty  Years  with  the  In- 
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with  no  complex  Formulae.  Illustrated.  8vo,  cloth $2.50 

Steam  Tables  and  Engine   Constant.      Compiled 

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PRACTICAL  IRON  FOUNDING.      By  the  author  of 

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PREECE,  W.  H.    Electric  Lamps (In  Press.) 

PREECE,  W.  H.,  and  STUBBS,  A.  T.     Manual  of  Tele- 

phony.     Illustrations  and  plates.     12mo,  cloth $4.50 

PREMIER  CODE.     (See  Hawke,  Wm.  H.) 

PRESCOTT,  Prof.  A.  B.     Organic  Analysis.     A  Manual 

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pounds in  Common  Use ;  a  Guide  in  the  Qualitative  and  Quantitative 
Analysis  of  Organic  Materials  in  Commercial  and  Pharmaceutical 
Assays,  in  the  estimation  of  Impurities  under  Authorized  Standards, 
and  in  Forensic  Examinations  for  Poisons,  with  Directions  for  Ele- 
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-  Outlines   of  Proximate  Organic  Analysis,  for  the 

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First  Book  in  Qualitative  Chemistry.    Eighth  edition. 


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—  and  OTIS  COE  JOHNSON.      Qualitative  Chemical 

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Chemistry  extended  throughout. . . $3.50 

PRITCHARD,   O.   G.      The    Manufacture    of  Electric 

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PUL.L.EN,  W.  W.  F.     Application  of  Graphic  Methods 

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PULSIFER,  W.  H.      Notes  for  a  History  of  Lead.  8vo> 
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PYNCHON,    Prof.    T.  R.      Introduction  to    Chemical 

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24  D.  VAN  NOSTRAND  COMPANY'S 


RADFORD,   Lieut.  CYRUS  S.      Handbook  on  Naval 

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U.  S.  N.  Third  edition.  12mo,  flexible  leather $2.00 

RAFTER,  GEO.  W.  and  M.  N.  BAKER.     Sewage  Dis- 

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Second  edition.  8vo,  cloth $6.00 

RAM,  GILBERT  S.    The  Incandescent  Lamp  and  its 

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RANDALL,  J.  E.    A  Practical  Treatise  on  the  Incan- 
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RANDALL,     P.     M.    Quartz    Operator's   Hand-book. 

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RANKINE,  W.  J.  MACQUORN.     Applied  Mechanics. 

Comprising  the  Principles  of  Statics  and  Cinematics,  and  Theory 
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-  Civil  Engineering.  Comprising  Engineering  Sur- 
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The  Steam-Engine  and  Other  Prime  Movers.    With 

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Useful  Rules  and  Tables  for  Engineers  and  Others. 

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A  Mechanical  Text  Book.     By  Prof.  Macquorn  Rankine 

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RAPHAEL,  F.  C.     Localisation  of  Faults  in  Electric 

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RECKENZAUN,  A.      Electric  Traction  on  Railways 

and  Tramways.     213  Illustrations,     12mo,  cloth $4.00 


SCIENTIFIC  PUBLICATIONS.  25 


REED'S    ENGINEERS'   HAND-BOOK,  to   the  Local 

Marine  Board  Examinations  for  Certificates  of  Competency  as  First 
and  Second  Class  Engineers.  By  W.  H.  Thorn.  With  the  answers 
to  the  Elementary  Questions.  Illustrated  by  297  diagrams  and  36  large 
plates.  Sixteenth  edition,  revised  and  enlarged.  8vo,  cloth.  .$5.00 

REED'S  Key  to  the  Sixteenth  Edition  of  Reed's  En- 
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tions given  in  the  examination  papers.  By  "W.  H.  Thorn.  8vo, 
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Useful  Hints  to  Sea-going  Engineers,  and  How  to 

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REINHARDT,  CHAS.  W.     Lettering  for  Draftsmen, 

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RICE,   J.   M.,   and   JOHNSON,  W.   W.      On  a    New 

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RINGWALT,   J.   Li.     Development  of  Transportation 

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RIPPER,    WILLIAM.      A  Course  of   Instruction   in 

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Folio,  cloth $6.00 

ROEBLING,   J.  A.     Long  and  Short    Span    Railway 

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views.  Imperial  folio,  cloth $25.00 

ROGERS,  Prof.  H.  D.     The  Geology  of  Pennsylvania. 

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with  portfolio  of  maps $15.00 


26  D.  VAN  NOSTRAND  COMPANY'S 


ROSE,  JOSHUA,  M.E.  The  Pattern-Makers'  Assistant. 

Embracing  Lathe  Work,  Branch  Work,  Core  Work,  Sweep  Work,  and 
Practical  Gear  Constructions,  the  Preparation  and  Use  of  Tools, 
together  with  a  large  collection  of  useful  and  valuable  Tables. 
Eighteenth  edition.  Illustrated  with  250  engravings.  8vo, 
cloth $2.50 

-  Key  to  Engines  and  Engine-running.    A  Practical 

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Engine  Adjustments,  and  other  Valuable  Information  necessary  for 
Engineers  and  Firemen.  12mo,  cl $2.50 

SABINE,   ROBERT.      History    and    Progress    of   the 

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SAELTZER,  ALEX.  Treatise  on  Acoustics  in  connec- 
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SALOMONS,  Sir  DAVID,  M.A.    Electric-Light  Instal- 

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Vol.    II.,  Apparatus,  296   illustrations.    12mo.,  cloth $2.25 

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SANFORD,  P.  GERALD.  Nitro-Explosives.  A  Prac- 
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SATJNNIER,  CLAUDIUS.     Watchmaker's  Handbook. 

A  Workshop  Companion  for  those  engaged  in  Watchmaking  and 
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SCHELLEN,  Dr.  H.  Magneto-Electric  and  Dynamo- 
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the  third  German  edition  by  N.  S.  Keith  and  Percy  Neymann,  Ph.D. 
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N.  S.  Keith.  Vol.  I.,  with  353  illustrations.  Second  edition..  .$5.00 

SCHUMANN,  F.  A  Manual  of  Heating  and  Ventilation 

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SCIENCE  SERIES,  The  Van  Nostrand.  [See  List,  p.  33] 


SCIENTIFIC  PUBLICATIONS.  27 


SCRIBNER,  J.  M.  Engineers'  and  Mechanics'  Com- 
panion. Comprising  United  States  Weights  and  Measures.  Mensura- 
tion of  Superfices  and  Solids,  Tables  of  Squares  and  Cubes,  Square 
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Water- Wheels,  Hydrostatics,  Hydraulics,  Statics,  Centres  of  Percus- 
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Scantling,  etc.,  Steam  and  the  Steam-Engine.  Twentieth  edition, 
revised.  16mo,  full  morocco SI. 50 

SEATON,  A.   E.    A  Manual  of  Marine  Engineering. 

Comprising  the  Designing,  Construction  and  Working  of  Marine 
Machinery.  With  numerous  tables  and  illustrations  reduced  from 
Working  Drawings.  Fourteenth  edition.  Revised  throughout,  with 
an  additional  chapter  on  Water  Tube  Boilers.  8vo,  cloth.  1899.  $6.00 

and  ROUNTHWAITE,  H.  M.  A  Pocketbook  of  Ma- 
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SHTJNK,  W.  F.   The  Field  Engineer.    A  Handy  Book 

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28  D.  VAN  NOSTRAND  COMPANY'S 


SIMMS,  W.  F.     Practical  Tunnelling.     Fourth  edition, 

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STALEY,  CADY,  and  PIERSON,  GEO.  S.  The  Separ- 
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STEWART,  R.  W.    A  Text  Book  of  Light.    Adapted 

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SCIENTIFIC  PUBLICATIONS.  29 


STILES,  AMOS.  Tables  for  Field  Engineers.  Designed 
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STONEY,   B.  D.    The  Theory  of  Stresses  in  Girders 

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30  D.  VAN  NOSTKAND  COMPANY'S 


THOMPSON,   EDWARD  P.,   M.   E.     Roentgen  Kays 

and  Phenomena  of  the  Anode  and  Cathode.  Principles,  Applications 
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SCIENTIFIC  PUBLICATIONS.  31 


URQUHART,  J.  W.  Electrotyping.  A  Practical  Man- 
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WALLJS-TAYLER,  A.  J.  Refrigerating  and  Ice- 
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WARING,  GEO.  E.,  Jr.     Sewerage  and  Land  Drainage. 

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SCIENTIFIC  PUBLICATIONS.  33 


WATT,  ALEXANDER.  The  Art  of  Leather  Manufact- 
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WEALE,   JOHN.      A  Dictionary    of  Terms  Used    in 

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the  Marine  Schools.  8vo,  half  roan $3.00 


Catalogue  of  the   Van  Nostrand 
Science  Series. 


*T*HE  I '  are  put  up  in  a  uniform,  neat,  and  attractive  form. 

-1  boards.  Price  jo  cents  per  volume.  The  subjects  are  of  an 
eminently  scientific  character,  and  embrace  a  wide  range  of  topics,  and 
are  amply  illustrated  when  the  subject  demands. 

No.  i.     CHIMNEYS  FOR  FURNACES  AND  STEAM  BOILERS. 

By  R.  Armstrong,  C.E.  Third  American  edition,  revised  and  partly 
rewritten,  with  an  appendix  on  Theory  of  Chimney  Draught,  by  F.  E. 
Idell,  M.E. 

No.  2.     STEAM-BOILER  EXPLOSIONS.    By  Zerah  Colburn.     N«w 
edition,  revised  by  Prof.  R.  H.  Thurston. 


No.  3.     PRACTICAL    DESIGNING     OF     RETAINING- WALLS. 

By  Arthu 
W.  Cain. 


Arthur  Jacob,  A.B.     Second  edition,  revised,  with  additions  by  Prof. 


No.  4.  PROPORTIONS  OF  PINS  USED  IN  BRIDGES.  Second 
edition,  with  appendix.  By  Charles  E.  Bender,  C.E. 

No.  5.  VENTILATION  OF  BUILDINGS.  By  W.  F.  Butler.  Second 
edition,  re-edited  and  enlarged  by  James  L.  Greenleaf,  C.E. 

No.  6.     ON     THE     DESIGNING     AND      CONSTRUCTION      OF 

STORAGE   RESERVOIRS.     By  Arthur  Jacob,  A.B.     Second  edition, 
revised,  with  additions  by  E.  Sherman  Gould. 

No.  7.  SURCHARGED  AND  DIFFERENT  FORMS  OF  RE- 
TAINING-WALLS.  By  James  S.  Tate,  C.E. 

No.  8.     A  TREATISE  ON  THE   COMPOUND  ENGINE.     By  John 

Turnbull,  jim.     Second  edition,  revised  by  Prof.  S.  W.  Robinson. 

No.  9.  A  TREATISE  ON  FUEL.  By  Arthur  V.  Abbott,  C.  E. 
Founded  on  the  original  treatise  of  C.  William  Siemens,  D.C.L. 

No.  10.  COMPOUND  ENGINES.  Translated  from  the  French  of  A. 
Mallet.  Second  edition,  revised,  with  Results  of  American  Practice,  by 
Richard  II.  Buel,  C.E. 

No.  ii.     THEORY  OF  ARCHES.     By  Prof.  W.  Allan. 

No.  12.  A  THEORY  OF  VOUSSOIR  ARCHES.  By  Prof.  W.  E. 
Cain.  Second  edition,  revised  and  enlarged.  Illustrated. 

No  13.  GASES  MET  WITH  IN  COAL-MINES.  By  J.  J.  Atkinson. 
Third  edition,  icvised  and  enlarged  by  Edward  H  Williams,  jun. 


D.    VAN  NO  STRAND  COMPANY'S 


No.  14.     FRICTION  OF  AIR  IN  MINES.     By  J.  J.  Atkinson, 
No.  15.     SKEW   ARCHES.     By  Prof.  E.  W.  Hyde,  C.E.     Illustrated 

No.  16.     A     GRAPHIC     METHOD     FOR     SOLVING     CERTAIN 

ALGEBRAIC    EQUATIONS.     By  Prof.  George  L.  Vose. 

No.  17.     WATER  AND  WATER-SUPPLY.     By  Prof.  W.  H.  Corfield 

of  the  University  College,  London. 

No.  18.     SEWERAGE    AND     SEWAGE    PURIFICATION.      By 
M.  N.  Baker,  Assoc.  Ed.  Engineering  News. 

No.  19.     STRENGTH     OF      BEAMS      UNDER      TRANSVERSE 

LOADS.     By  Prof.  W.  Allan,  author  of  "Theory  of  Arches." 

No.  20.     BRIDGE    AND    TUNNEL    CENTRES.      By  John   B.   Me- 
Master,  C.E. 

No.  21.     SAFETY   VALVES.     By  Richard  H.  Buel,  C.E.  Second  edition. 
No  22.     HIGH    MASONRY    DAMS.     By   E.  Sherman  Gould,  C.E. 

No.  23.  THE  FATIGUE  OF  METALS  UNDER  REPEATED 

STRAINS.  With  Various  Tables  ot  Results  and  Experiments.  From 
the  German  of  Prof.  Ludwig  Spangenburgh,  with  a  Preface  by  S.  li. 
Shreve,  A.M. 

No.  24.  A  PRACTICAL  TREATISE  ON  THE  TEETH  OF 

WHEELS.     By  Prof.  S.  W.  Robinson.     Second  edition,  revised. 

No.  25.     ON    THE   THEORY   AND   CALCULATION   OF   CAN- 
TILEVER BRIDGES.     By  R.  M.  Wilcox,  Ph.B. 

No.  26.     PRACTICAL    TREATISE  ON    THE    PROPERTIES  Or 

CONTINUOUS    BRIDGES.     By  Charles  Bender,  C.E. 

No.  27.     ON     BOILER     INCRUSTATION      AND     CORROSION 

By  F.  J.  Rowan.     New  edition,  revised  and  partly  rewritten  by  F.  L. 
Idell,  M.  E. 
No.  28.     TRANSMISSION      OF     POWER     BY     WIRE     ROPES 

By  Albert  W.  Stahl,  U.S.N.     Second  edition. 

No.  29.     STEAM        INJECTORS.       Translated    from    the     French     oi 
M.  Leon  Pochet. 

No.  30.     TERRESTRIAL   MAGNETISM,   AND   THE    MAGNET- 
ISM   OF   IRON   VESSELS.     By  Prof.  Fairman  Rogers. 

.No.  31.      THE      SANITARY      CONDITION      OF      DWELLING- 

HOUSES    IN   TOWN  AND  COUNTRY.     By  George  E.  Waring,  jun, 

No.  32.     CABLE-MAKING    FOR    SUSPENSION    BRIDGES.     By 

W.  Hildenbrand,  C.E. 

No.  33.     MECHANICS    OF   VENTILATION.     By  George  W.  Rafter, 
C.E.     New  edition  (1895),  revised  by  author. 

No.  34.     FOUNDATIONS.      By  Prof.  Jules   Gaudard,  C.E.      Translated 
from  the  French. 

No.  35.     THE     ANEROID     BAROMETER  :      ITS     CONSTRUC- 
TION AND  USE.     Compiled  by  George  W.  Plympton.     Fourth  edition 

No.  36.     MATTER    AND    MOTION.      By  J.  Clerk    Maxwell,    M.A. 
Second  American  edition. 


SCIENCE  SERIES. 


Mo.  37.     GEOGRAPHICAL    SURVEYING:    ITS    USES,    METH- 
ODS, AND  RESULTS.     By  Frank  De  Yeaux  Carpenter,  C.E. 

No.  38.     MAXIMUM    STRESSES    IN    FRAMED    BRIDGES.     By 

Prof.  William  Cain,  A.M.,  C.E.    New  and  revised  edition. 

No.  39.     A      HANDBOOK      OF      THE      ELECTRO-MAGNETIC 

TELEGRAPH.     By  A.  E.  Loring. 

No.  40.     TRANSMISSION  OF  POWER  BY  COMPRESSED  AIR. 

By  Robert  Zahner,  M.E.    Second  edition. 

No.  41.  STRENGTH  OF  MATERIALS.  By  William  Kent,  C.E., 
Assoc.  Ed.  Engineering  News. 

No.  42.     VOUSSOIR  ARCHES  APPLIED  TO  STONE  BRIDGES, 

TUNNELS,  CULVERTS,  AND  DOMES.     By  Prof.  William  Cain. 

No.  43.  WAVE  AND  VORTEX  MOTION.  By  Dr.  Thomas  Craig  of 
Johns  Hopkins  University. 

No.  44.  TURBINE  WHEELS.  By  Prof.  W.  P.  Trowbridge,  Columbia 
College.  Second  edition. 

No.  45.  THERMODYNAMICS.  By  Prof.  H.  T.  Eddy,  University  of 
Cincinnati. 

No.  46.  ICE-MAKING  MACHINES.  New  edition,  revised  and  en- 
larged  by  Prof.  J.  E.  Denton.  From  the  French  of  M.  Le  Doux. 

No.  47.    LINKAGES;    THE    DIFFERENT   FORMS   AND  USES 

OF  ARTICULATED  LINKS.     By  J.  D.  C.  de  Roos. 

No.  48.     THEORY    OF    SOLID    AND    BRACED    ARCHES.      By 

William  Cain,  C.E. 

No.  49.     ON    THE    MOTION    OF    A    SOLID   IN    A    FLUID.    By 

Thomas  Craig,  Ph.D. 

No.  50.  DWELLING-HOUSES:  THEIR  SANITARY  CON- 
STRUCTION AND  ARRANGEMENTS.  By  Prof.  W.  H.  Corfield. 

No.  51.     THE    TELESCOPE  :    ITS    CONSTRUCTION,   ETC.    By 

Thomas  Nolan. 

No.  52.     IMAGINARY   QUANTITIES.     Translated  from  the  French  of 

.  .     M.  Argand.     By  Prof.  Hardy. 

No.  53.     INDUCTION  COILS  :   HOW  MADE  AND  HOW  USED. 

Fifth  edition. 

No.  54.  KINEMATICS  OF  MACHINERY.  By  Prof.  Kennedy.  With 
an  introduction  by  Prof.  R.  H.  Thurston. 

No.  55.     SEWER  GASES  :  THEIR  NATURE  AND  ORIGIN.     By 

A.  de  Varona. 

No.  56.  THE  ACTUAL  LATERAL  PRESSURE  OF  EARTH- 
WORK. By  Benjamin  Baker,  M.  Inst.  C.E. 

No.  57.  INCANDESCENT  ELECTRIC  LIGHTING.  A  Practical 
Description  of  the  Edison  System.  By  L.  H.  Latimer,  to  which  is 
added  the  Design  and  Operation  of  Incandescent  Stations,  by  C.  J. 
Field,  and  the  Maximum  Efficiency  of  Incandescent  Lamps,  by  John 
W.  Ho  well. 


N°-  5™-/r|I!FoVENTILATION  OF  COAL-MINES.    By  W.  Fairlev. 

M.llr     ,     F.S.S. 


D.    VAN  NO  STRAND  COMPANY'S 


No.  59.  RAILROAD  ECONOMICS;  OR,  NOTES,  WITH  COM- 
MENTS. By  S.  W.  Robinson,  C.E. 

No.  60.     STRENGTH    OF    WROUGHT-IRON     BRIDGE     MEM- 

BERS.     By  S.  W.  Robinson,  C  E. 

No.  61.  POTABLE  WATER  AND  METHODS  OF  DETECT- 
ING IMPURITIES.  By  M.  N.  Baker,  Ph.B. 

No.  62.  THE  THEORY  OF  THE  GAS-ENGiNE.  By  Dugald  Clerk. 
Second  edition.  With  additional  matter.  Edited  by  F.  E.  Idell,  M.E. 

No.  63.  HOUSE  DRAINAGE  AND  SANITARY  PLUMBING. 

By  W.  P.  Gerhard.     Seventh  edition,  revised. 

No.  64.     ELECTRO-MAGNETS.  ByTh.du  Moncel.  2d  revised  edition. 

No.  65.  POCKET  LOGARkTHMS  TO  FOUR  PLACES  OF  DECI- 
MALS. 

No.  66.  DYNAMO-ELECTRIC  MACHINERY.  By  S.  P.  Thompson, 
With  notes  by  F.  L.  Pope.  Third  edition. 

No.  67.     HYDRAULIC      TABLES      BASED      ON      "  KUTTER'S 

FORMULA."     By  P.  J.  Flynn. 

No.  68.  STEAM-HEATING.  By  Robert  Briggs.  Second  edition,  revised, 
with  additions  by  A.  R.  Wolff. 

No.  69.  CHEMICAL  PROBLEMS.  By  Prof.  J.  C.  Foye.  Fourth 
edition,  revised  and  enlarged. 

No.  70.     EXPLOSIVE  MATERIALS.    The  Phenomena  and  Theories 

of  Explosion,  and  the  Classification,  Constitution  and  Preparation  of 
Explosives.     By  First  Lieut.  John  P.  Wisser,  U.S.A. 

No.  71.  DYNAMIC  ELECTRICITY.  By  John  Hopkinson,  J.  A. 
Schoolbred,  and^R.  E.  Day. 

No.  72.  TOPOGRAPHICAL  SURVEYING.  By  George  J.  Specht, 
Prof.  A.  S.  Hardy,  John  B.  McMaster,  and  H.  F.  Walling. 

No.  73.  SYMBOLIC  ALGEBRA;   OR,  THE  ALGEBRA  OF 

ALGEBRAIC  NUMBERS.     By  Prof.  W.  Cain. 

No.  74.  TESTING  MACHINES  :  THEIR  HISTORY,  CON- 
STRUCTION, AND  USE.  By  Arthur  V.  Abbott. 

No.  75.  RECENT  PROGRESS  IN  DYNAMO-ELECTRIC  MA- 
CHINES. Being  a  Supplement  to  Dynamo-Electric  Machinery.  By 
Prof.  Sylvanus  P.  Thompson. 

No.  76.  MODERN  REPRODUCTIVE  GRAPHIC  PROCESSES. 

By  Lieut.  James  S.  Pettit,  U.S.A. 

No.  77.  STADIA  SURVEYING.  The  Theory  ot  Stadia  Measurements. 
By  Arthur  Winslow. 

No.  78.     THE    STEAM-ENGINE    INDICATOR,  AND   ITS   USE 

By  W.  B.  Le  Van. 

No.  79.     THE  FIGURE  OF  THE  EARTH.     By  Frank  C.  Roberts, C.E. 

No.  80.    HEALTH*    FOUNDATIONS    FOR    HOUSES.     By  Gle»a 

Brown. 


SCIENCE  SERIES. 


No.  81.     WATER      METERS  :       COMPARATIVE      TESTS     OF 

ACCURACY,  DELIVERY,   ETC.     Distinctive  features  of  the  Worth- 
ington,  Kennedy,  Siemens,  and  Hesse  meters.     By  Ross  E.  Browne. 

No.  82.     THE     PRESERVATION    OF    TIMBER    BY    THE   USE 

OF  ANTISEPTICS.     By  Samuel  Bagster  Boulton,  C.E. 

No.  83.  MECHANICAL  INTEGRATORS.  By  Prof.  Henry  S.  H. 
Shaw,  C.E. 

No.  84.  FLOW  OF  WATER  IN  OPEN  CHANNELS,  PIPES, 
CONDUITS,  SEWERS,  ETC.  With  Tables.  By  P.  J.  Flynn,  C.E. 

No.  85      THE  LUMINIFEROUS  AETHER.     By  Prof,  de  Volson  Wood. 

No.  86.  HAND-BOOK  OF  MINERALOGY;  DETERMINATION 
AND  DESCRIPTION  OF  MINERALS  FOUND  IN  THE  UNITED 
STATES.  By  Prof.  J.  C.  Foye. 

No.  87.  TREATISE  ON  THE  THEORY  OF  THE  CON- 
STRUCTION OF  HELICOIDAL  OBLIQUE  ARCHES.  By  John 
L.  Culley,  C.E. 

No.  88.  BEAMS  AND  GIRDERS.  Practical  Formulas  for  their  Re- 
sistance.  By  P.  H.  Philbrick. 

No.  89.  MODERN  GUN-COTTON:  ITS  MANUFACTURE, 
PROPERTIES,  AND  ANALYSIS.  By  Lieut.  John  P.  Wisser,  U.S.A. 

No.  90.  ROTARY  MOTION,  AS  APPLIED  TO  THE  GYRO- 
SCOPE. By  Gen.  J.  G.  Barnard. 

No.  91.  LEVELING:  BAROMETRIC,  TRIGONOMETRIC,  AND 
SPIRIT.  By  Prof.  I.  O.  Baker. 

No.  92.     PETROLEUM  :     ITS     PRODUCTION     AND     USE.       By 

Boverton  Redwood,  F.I.C.,  F.C.S. 

No.  93.  RECENT  PRACTICE  IN  THE  SANITARY  DRAIN- 
AGE OF  BUILDINGS.  With  Memoranda  on  the  Cost  of  Plumbing 
Work.  Second  edition,  revised.  By  William  Paul  Gerhard,  C.  E. 

No.  94.  THE  TREATMENT  OF  SEWAGE.  By  Dr.  C.  Meymott 
Tidy. 

No.  95.  PLATE  GIRDER  CONSTRUCTION.  By  Isami  Hiroi,  C.E. 
Second  edition,  revised  and  enlarged.  Plates  and  Illustrations. 

No.  96.  ALTERNATE  CURRENT  MACHINERY.  By  Gisbert 
Kapp,  Assoc.  M.  Inst.,  C.E. 

No.  97.  THE  DISPOSAL  OF  HOUSEHOLD  WASTE.  By  W, 
Paul  Gerhard,  Sanitary  Engineer. 

No.  98.  PRACTICAL  DYNAMO-BUILDING  FOR  AMATEURS. 
HOW  TO  WIND  FOR  ANY  OUTPUT.  By  Frederick  Walker. 
Fully  illustrated. 

No.  99.  TRIPLE-EXPANSION  ENGINES  AND  ENGINE 
TRIALS.  By  Prof.  Osborne  Reynolds.  Edited,  with  notes,  etc.,  by 
F.  E.  Well.  M.  E. 


SCIENCE  SERIES. 


No.  100.  HOW  TO  BECOME  AN  ENGINEER  ;  OH  THE 
THEORETICAL  AND  PRACTICAL  TRAINING  NECESSARY  IN 
FITTING  FOR  THE  DUTIES  OF  THE  CIVIL  ENGINEER.  The 
Opinions  of  Eminent  Authorities,  and  the  Course  of  Study  in  the 
Technical  Schools.  By  Geo.  W.  Plympton,  Am.  Soc.  C.E. 

No.  101.  THE   SEXTANT  AND   OTHER   REFLECTING 

MATHEMATICAL  INSTRUMENTS.  With  Practical  Suggestions 
and  Wrinkles  on  their  Errors,  Adjustments,  and  Use.  With  thirty- 
three  illustrations.  By  F.  R.  Brainard,  U.S.N. 

No.    102.      THE       GALVANIC      CIRCUIT      INVESTIGATED 

MATHEMATICALLY.  By  Dr.  G.  S.  Ohm, -Berlin,  1827.  Translated 
by  William  Francis.  W.-li  Preface  and  Notes  by  the  Editor,  Thomas 
D.  Lockwood,  M.I.E.E. 

No.  103.  THE  MICROSCOPICAL  EXAMINATION  OF  POTA- 
BLE WATER.  With  Diagrams.  By  Geo.  W.  Rafter. 

No.  104.  VAN  NOSTRAND'S  TABLE-BOOK  FOR  CIVIL  AND 
MECHANICAL  ENGINEERS.  Compiled  by  Geo.  W.  Plympton,  C.E, 

No.    105.     DETERMINANTS,   AN   INTRODUCTION  TO  THE 

STUDY  OF.     With  examples.     By  Prof.  G.  A.  Miller. 

No.  106.  TRANSMISSION  BY  AIR-POWER.  Illustrated.  By 
Prof.  A.  B.  W.  Kennedy  and  W.  C.  Unwin. 

No.    107.     A  GRAPHICAL   METHOD    FOR   SWING-BRIDGES. 

A  Rational  and  Easy  Graphical  Analysis  of  the  Stresses  in  Ordinary 
Swing-Bridges.  With  an  Introduction  on  the  General  Theory  of  Graphi- 
cal Statics.  4  Plates.  By  Benjamin  F.  LaRue,  C.E. 

No.    108.     A    FRENCH    METHOD    FOR    OBTAINING    SLIDE: 

VALVE  DIAGRAMS.  8  Folding  Plates.  By  Lloyd  Bankson,  B.S., 
Assist.  Naval  Constructor,  U.S.N. 

No.  109.  THE  MEASUREMENT  OF  ELECTRIC  CURRENTS. 

ELECTRICAL  MEASURING  INSTRUMENTS.  By  Jas.  Swinburne.  METERS 
FOR  ELECTRICAL  ENERGY.  By  C.  H.  Wordingham.  Edited  by' 
T.  Commerford  Martin.  Illustrated. 

No.  no.  TRANSITION  CURVES.  A  Field  Book  for  Engineers, 
containing  Rules  and  Tables  for  laying  out  Transition  Curves.  By 
Walter  G.  Fox. 

No.  in.  GAS-LIGHTING  AND  GAS-FITTING,  including  Specifica, 
tions  and  Rules  for  Gas  Piping,  Notes  on  the  Advantages  of  Gas  for 
Cooking  and  Heating,  and  useful  Hints  to  Gas  Consumers.  Second 
edition,  rewritten  and  enlarged.  By  Wm.  Paul  Gerhard. 

No.  112.  A  PRIMER  ON  THE  CALCULUS.  By  E.  Sherman 
Gould,  C.E. 

No.  113.     PHYSICAL   PROBLEMS   AND    THEIR    SOLUTION. 

By  A.  Bourgougnon,  formerly  Assistant  at  Bellevue  Hospital. 

No.  114.  MANUAL  OF  THE  SLIDE  RULE.  By  F.  A.  Halsey  of 
the  American  Machinist. 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

INITIAL    FlNE~OF     25     CENTS 


OVERDUE. 

OCT 


1933 


10  1836 


LD  21-50m-l, 


Pt 

79  01 


' 


